WO2024165911A1

WO2024165911A1 - Tuned sole shank component and hybrid toe box assembly for dance footwear

Info

Publication number: WO2024165911A1
Application number: PCT/IB2023/062271
Authority: WO
Inventors: David Fox
Original assignee: Pointe Noir Pty Ltd
Current assignee: Pointe Noir Pty Ltd
Priority date: 2023-02-07
Filing date: 2023-12-05
Publication date: 2024-08-15
Anticipated expiration: 2025-08-07

Abstract

A dance shoe having an upper and an underfoot portion, the underfoot portion includes a sole shank, consisting of a relatively stiff structure, extending longitudinally in the shoe over at least a forefoot portion of the shoe and at least partially over a midfoot portion. The sole shank has a plurality of hinges, each with a unidirectional stop disposed widthwise in the sole shank. Each hinge comprises a pair of opposing walls defining a first portion where the opposing walls are separated from each other by a first distance in a neutral position and converge to abutment in plantar flexion and a second portion where the opposing walls are separated from each other by a second distance larger than the first distance and remain separated from each other in plantar flexion. To facilitate en pointe movements, the sole shank may be coupled to a rigid distal part of the shoe, such as a toe box. The toe boxes may also have hinges. They may also have apertures that allow for tuned flex or interlock with other parts. The inventive subject matter is also directed to dance shoes, as well as the sole shanks or toe boxes themselves, and to methods of making the sole shanks and using the sole shanks in assemblies.

Description

TUNED SOLE SHANK COMPONENT AND HYBRID TOE BOX ASSEMBLY FOR DANCE FOOTWEAR Inventor: David Fox PRIORITY [0001] This application claims benefit of and priority to U.S. Provisional Patent Application No. 63/443,842, filed February 7, 2023, of which patent applications is hereby incorporated by reference in its entirety as if fully set forth herein, for all purposes. BACKGROUND [0002] The inventive subject matter is generally directed to a dance shoe. It is particularly directed to a pointe shoe that includes a rigid toe box and a sole shank extending longitudinally from a distal portion to a proximal portion of the shoe. [0003] Ballet dancers use specifically designed pointe shoes to assist the dancer to stand on the tips of their toes, referred to as dancing “en pointe.” The pointe shoe typically provides support to the dancer’s foot through a toe box, which is a rigid structure encasing the front of toes and some or all of the rest of the forefoot, and a shank, which extends longitudinally therefrom. The toe box generally hugs the foot across the metatarsal so that the sides of the dancer’s foot are held in place. The shank is an elongate, rigid element that is structurally coupled (e.g., as a separately attached or as an integrated piece) to the toe box and extends rearwardly from the toe box, typically at least across the midfoot region to the rearfoot region of the shoe, in the bottom, foot-supporting portion of the shoe. When dancing en pointe, the shank and toe box help support the foot and help distribute the dancer’s weight across a broader area foot instead of the weight being concentrated in the toes. To effectively spread the weight, the shoe should fit tightly to the dancer’s foot. [0004] Extensive training and practice are required to develop the strength and technique needed for pointe work. Proper pointe technique requires not only proper foot placement such that the toes are perpendicular to the floor to maximize the contact surface area of the platform (i.e., the flattened tip of the toe box) with the floor, but also proper body alignment to form a straight “line” extending from the center of the hip through the toes. If proper pointe technique is not used, serious injuries may occur. In addition, pointe shoes are generally not used until the shoes have been broken in. The process of breaking-in a new shoe is effort intensive and includes a variety of actions like bending and twisting the shoe until it has a desired flexibility. Because of such manipulations, the toe box and/or shank of a pointe shoe may become weakened and vulnerable to degradation, making the shoe less supportive with use. Atty. Docket No.: BCH2039PCT 1 [0005] One of the problems with traditional pointe shoes is the difficulty to balance between the stiffness and flexibility of the shoe. While the rigid toe box and shank of a pointe shoe provide structural support for the foot in plantar flexion (e.g., en pointe or tendu positions), the lack of flexibility of the pointe shoe may limit the range of other foot flexions (e.g., neutral or dorsiflexion), in particular when frequent transitions between foot flexions occur, e.g., when the dancer is walking, running, or jumping. [0006] Another common problem with traditional pointe shoes is the lack of a mechanism to assist the dancer to perform pointe work with proper foot placement and body alignment. When transitioning to en pointe, a dancer may be unaware of whether the foot reaches a fully extended, vertical orientation, which may result in over-plantar flexion. Both under- and over-plantar flexion of the foot are undesirable for en pointe since they not only undermine the aesthetic aspect of the dance but also can create significant possibilities of strains and injury to the dancer’s foot. [0007] The following is a list of related prior art, although none of them successfully resolves the foregoing problems: [0008] U.S. Patent Pub. No.20090151200, Niedermeyer et al. [0009] U.S. Pat. No.7,036,244, Finch [0010] U.S. Pat. No.9,009,988, Jacobs et al. [0011] U.S. Patent Pub. No.20050022421, Bruckner. [0012] Accordingly, there is a need for a pointe shoe and other dance shoes that support the foot, while conforming to the foot through a range of foot flexions, including those that correspond to the en pointe position. There is also a need for pointe shoes and similar dance shoes that assist the dancer in performing pointe work, while inhibiting the dancer’s foot from over-plantar flexion. SUMMARY [0013] The inventive subject matter addresses the aforementioned needs and provides advances over the prior art. [0014] In one possible embodiment, the inventive subject matter is directed to a dance shoe having an upper and an underfoot portion, the underfoot portion including a sole shank. The sole shank includes a stiffening structure, extending longitudinally in the shoe over at least a forefoot portion of the shoe and at least partially over a midfoot portion. A plurality of hinges, each with a unidirectional stop are disposed widthwise in the sole shank in at least the forefoot portion so that a forefoot portion of the sole shank locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of the foot and follow dorsiflexion of an intended wearer’s forefoot. Each hinge comprises a pair of opposing walls that have one or more first Atty. Docket No.: BCH2039PCT 2 opposing-wall portions that that are spaced apart in a neutral, first position and are convergeable to abutment when moving from the neutral position to a second position representing a selected degree of plantar flexion, and (2) one or more second portion opposing-wall portions where the opposing walls are separated from each other in the neutral position and remain separated from each other in the selected degree of plantar flexion. A rigid distal part of the shoe is coupled to the sole shank. [0015] In another possible embodiment, the inventive subject matter is directed to a sole shank that includes a stiffening structure configured to extend longitudinally in a shoe over at least a forefoot portion of the shoe and at least partially over a midfoot portion, and at least one hinge with a unidirectional stop being disposed widthwise in the sole shank in at least the forefoot portion so that the sole shank locks to support plantar flexion and hinges to facilitate dorsiflexion of the forefoot portion. The sole shank is coupled to a rigid distal part of the shoe, wherein each hinge comprises a pair of opposing walls defining a (1) first portion where the opposing walls are separated in a neutral position and are convergeable to abutment in a plantar flexion, and (2) a second portion where the opposing walls are separated from each other in a neutral position and remain separated from each other in the plantar flexion. The sole shank optionally may be pre-shaped in a non-planar, three-dimensional form to mimic and thereby facilitate plantar flexion of the intended wearer’s foot. [0016] In another possible embodiment, the inventive subject matter is directed to a dance shoe with a distal part having a rigid toe box for encasing at least a portion of a forefoot of an intended wearer and supporting a foot of the intended wearer. An intermediate part is coupled to the distal part and configured for receiving at least a portion of a midfoot of the intended wearer. A proximal part is coupled to the intermediate part and configured for receiving at least a rearfoot portion of the intended wearer. The shoe includes a sole unit having a sole shank extending longitudinally from the distal part to the proximal part, wherein the sole shank has a plurality of hinges each with a unidirectional stop disposed widthwise in the sole shank in at least a forefoot portion that locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of the forefoot portion and follow dorsiflexion of an intended wearer’s forefoot. A portion of the sole shank in a midfoot position permits plantar flexion of an arch of the intended wearer’s foot, wherein each hinge comprises a pair of opposing walls defining (1) a first portion where the opposing walls are separated in a neutral position and are convergeable to abutment in plantar flexion, and (2) a second portion where the opposing walls are separated from each other in the neutral position and remain separated from each other in the plantar flexion. Atty. Docket No.: BCH2039PCT 3 [0017] In another possible embodiment, the inventive subject matter is directed to a toe box for a dance shoe. The toe box has a hollow rigid structure comprising a bottom side, an opposing top side, a medial side and a lateral side disposed between the top side and the bottom side, and a flat front side coupled to each of the top side, bottom side, lateral side and medial side and enclosing a distal end of the hollow rigid structure. The hollow rigid structure is configured to receive the toes and some or all of the rest of the forefoot of an intended wearer. An outer surface of the bottom side includes a plurality of hinges, each with a unidirectional stop being disposed widthwise across the bottom side so that the bottom side locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of an intended wearer’s forefoot. [0018] In another possible embodiment, the inventive subject matter is directed to a dance shoe having a toe box. The toe box has a bottom side, an opposing top side, a medial side and a lateral side disposed between the top side and the bottom side, and a flat front side coupled to each of the top side, bottom side, lateral side and medial side and enclosing a distal end of the hollow rigid structure. An outer surface of the bottom side includes a first plurality of hinges, each with a unidirectional stop being disposed widthwise across the bottom side so that the bottom side locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of an intended wearer’s forefoot. [0019] A sole shank may be coupled to the bottom side of the aforementioned hinged toe box. The sole shank is a stiffening structure extending longitudinally in the shoe over at least a forefoot portion of the shoe and at least partially over a midfoot portion. The sole shank may include a second plurality of hinges, each with a unidirectional stop being disposed widthwise in the sole shank in at least the forefoot portion so that a forefoot portion of the sole shank locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of the foot and follow dorsiflexion of an intended wearer’s forefoot. A portion of the sole shank in a midfoot position permits plantar flexion of an arch of the intended wearer’s foot, the sole shank being coupled to a rigid distal part of the shoe. [0020] In another possible embodiment, the inventive subject matter is directed to a dance shoe having a distal part having a rigid toe box for encasing at least a portion of a forefoot of an intended wearer and supporting a foot of the intended wear. An intermediate part is coupled to the distal part and configured for receiving at least a portion of a midfoot of the intended wearer. A proximal part is coupled to the intermediate part and configured for receiving at least a rearfoot portion of the intended wearer. The shoe includes a sole unit comprising a sole shank extending longitudinally from the distal part to the proximal part; and an interlocking component configured to interconnect the sole unit to the rigid toe box. Atty. Docket No.: BCH2039PCT 4 [0021] In any of the foregoing or other embodiments contemplated herein, the rigid distal part may be a rigid toe box. [0022] In any of the foregoing or other embodiments contemplated herein, the hinges may be disposed widthwise and without intersecting one another. [0023] In any of the foregoing or other embodiments contemplated herein, the first opposing- wall portions may be inflection points or sections disposed between or adjacent second portion opposing-wall portions. [0024] In any of the foregoing or other embodiments contemplated herein, there may be three or more living hinges each with an undulating form. [0025] In any of the foregoing or other embodiments contemplated herein, the length of the sole shank may be about equal to the full length of the sole unit. [0026] In any of the foregoing or other embodiments contemplated herein, the length of the sole shank may be longer than half but shorter than full length of the sole unit. [0027] In any of the foregoing or other embodiments contemplated herein, the width of the sole shank may be about equal to the width of a sole unit in the dance shoe. [0028] In any of the foregoing or other embodiments contemplated herein, the width of the sole shank may be substantially narrower than the width of the sole unit, and the sole shank is disposed substantially on a central axis of the shoe. [0029] In any of the foregoing or other embodiments contemplated herein, the sole shank may be pre-shaped in a non-planar, three-dimensional form to facilitate plantar flexion of the intended wearer’s foot. The three-dimensional form may represent an intended wearer’s foot in a plantar- flexed position, in particular a curved shape near an arch portion of the intended wearer’s foot. [0030] In any of the foregoing or other embodiments contemplated herein the opposing walls of a hinge may have faces that are not parallel to each other and converge to a closed bottom. [0031] In any of the foregoing or other embodiments contemplated herein, the opposing walls of a hinge may have faces that are parallel to each other. [0032] In any of the foregoing or other embodiments contemplated herein, a pair of opposing walls in a second portion of a hinge may correspond to an area where some of the sole shank material is removed. [0033] In any of the foregoing or other embodiments contemplated herein, the sole shank may be made of a board material in whole or part. [0034] In any of the foregoing or other embodiments contemplated herein, in the second portion of a hinge, one of the opposing walls may have a flat side below an opposing concave curve of the other of the opposing walls. Atty. Docket No.: BCH2039PCT 5 [0035] In any of the foregoing or other embodiments contemplated herein, in the second portion of a hinge, the opposing walls may have a first distal side opposing wall convexly curving, and a second proximal side opposing wall concavely curving such that the first convexly curving side partially nests in the concavely curving side. [0036] In any of the foregoing or other embodiments contemplated herein, the opposing walls defining the first portion may be separated by a first distance in the neutral position and the separation of the opposing walls defining the second portion in the neutral position may be larger than the first distance separating the walls in the first portion. [0037] In any of the foregoing or other embodiments contemplated herein, a rigid toe box may include an aperture positioned over a central portion of the sole shank configured to expose one or more hinges in an adjacent sole shank. [0038] In any of the foregoing or other embodiments contemplated herein, the bottom side of a toe box may include a centrally disposed aperture between lateral and medial portions of the bottom side, the aperture being disposed over a majority of the length of a forefoot area of the bottom side. Hinges may be disposed on the lateral and medial portion, which may be linear or non-linear or a combination of linear and non-linear hinges. [0039] In any of the foregoing or other embodiments contemplated herein, a first plurality of hinges may be offset from a second plurality of hinges in the sole shank and/or the rigid toe box. [0040] In any of the foregoing or other embodiments contemplated herein, a first plurality of hinges may be collinear with a second plurality of hinges. [0041] In any of the foregoing or other embodiments contemplated herein, the rigid toe box may predominantly include a material having a first rigidity and wherein the sole unit may be predominantly a material having a second rigidity. The material having the first rigidity may be a different material from the material having the second rigidity. [0042] In any of the foregoing or other embodiments contemplated herein, a shoe assembly may have a protruding or insertable locking component protruding from one of a bottom surface of the sole unit and a bottom surface of the rigid toe box. The assembly may have an aperture in the other of the bottom surface of the sole unit and the bottom surface of the rigid toe box, the aperture being configured to receive the protruding or insertable element so as to interlock the sole unit and the toe box. [0043] In any of the foregoing or other embodiments contemplated herein, and interlocking component may be configured as a plurality of protruding locking components and a plurality of apertures. [0044] In any of the foregoing or other embodiments contemplated herein, the interlocking component may be configured to removably interconnect the sole unit to the rigid toe box. Atty. Docket No.: BCH2039PCT 6 [0045] In any of the foregoing or other embodiments contemplated herein, [0046] Other embodiments are contemplated in the Detailed Description below, the appended Figures, and in the claims, as originally written or amended, the claims as such being incorporated by reference into this Summary. The foregoing is not intended to be an exhaustive list of embodiments and features of the inventive subject matter. Persons skilled in the art can appreciate other embodiments and features from the following detailed description, in conjunction with the drawings. BRIEF DESCRIPTION OF THE DRAWINGS [0047] The following figures show embodiments according to the inventive subject matter, unless noted as showing prior art. The figures presented are for illustrative and explanatory purposes and are not necessary in scale. [0048] FIGS.1A-1B show respectively bottom and top views of a sole shank with unidirectional flex capability. [0049] FIG.2 shows an exploded view of the sole shank of FIG.1A. [0050] FIG.3A shows human feet in footwear in the dorsiflexion position. [0051] FIGS.3B-3D show side elevations of the sole shank of FIG.1 in, respectively, dorsiflexion, neutral and plantar flexion configurations. [0052] FIG.4A shows a side elevation of the sole shank of FIG.1 in a plantar flexion configuration. [0053] FIG.4B shows a human foot in footwear in the plantar flexion (en pointe) position, illustrating how the sole shank of FIG.4A would work in the footwear. [0054] FIG.5 shows a side, longitudinal cutaway of a dance shoe, such as a pointe shoe, incorporating a sole shank. [0055] FIGS.6A-6C show the top view of a dance shoe having a sole shank according to one possible embodiment of the inventive subject matter, and separate views of the sole shank and a support board. [0056] FIGS.7A-7B show a side view of the dance shoe of FIG.6, and a separate view of its sole shank with multiple zones of varying flexibility. [0057] FIG.8 shows a foot en pointe and wearing a pointe shoe which has a pre-shaped sole shank according to one possible embodiment of the inventive subject matter, with a separate view of the sole shank. [0058] FIG.9 shows an alternative embodiment of a sole unit including a sole shank attached to layers of board. [0059] FIG.10 shows isolated view of components included in the sole unit of FIG.9. [0060] FIG.11 shows an anatomical mapping of a typical foot. Atty. Docket No.: BCH2039PCT 7 [0061] FIG.12 shows a bottom view of a representative sole shank having a plurality of living hinge that may be formed in a board material, with the sole shank being in a neutral position (i.e., an unweighted or unstressed position). [0062] FIG.13 shows a bottom view of a sole unit assembly with examples of the layers that may form the assembly, with one layer being the sole shank of FIG.12. [0063] FIG.14 shows a top view of an example of a toe box assembly in a neutral position. [0064] FIG.15 shows a top view of an example of an assembly that includes a toe box and sole shank in a neutral position. [0065] FIG.16 shows a bottom view of the assembly of FIG.15 in a neutral position. [0066] FIG.17 shows a first side view of the assembly of FIG.15 with a visible bottom side in a neutral position. [0067] FIG.18 shows a second side perspective view of the assembly of FIG.15 with a visible top side in a neutral position. [0068] FIG.19 shows a front view of the assembly of FIG.15. [0069] FIG.20 shows a bottom view of a second example of an assembly that includes a toe box and sole shank in a neutral position. [0070] FIG.21 shows a bottom view of a third example of an assembly that includes a toe box and sole shank in a neutral position. [0071] FIG.22 shows a bottom view of a fourth example of an assembly that includes a toe box and sole shank in a neutral position. [0072] FIG.23 shows a bottom view of a fifth example of an assembly that includes an interlocking toe box and sole shank in a neutral position. [0073] FIG.24 shows an example of a shank assembly that may be used to interlock with certain toe boxes. [0074] FIG.25 shows a bottom view of the shank assembly of FIG.24interlocking with a certain toe box. [0075] FIG.26 shows a perspective bottom view of a partially disassembled shank and interlocking toe box system of FIG.25. [0076] FIG.27 shows a perspective top exploded view of the shank and interlocking toe box system of FIG.25. [0077] FIG.28 shows a bottom perspective view of the interlocking toe box of FIG.25 in dorsiflexion. [0078] FIG.29 shows a side perspective view of an interlocking toe box and shank of FIG.25 in dorsiflexion. Atty. Docket No.: BCH2039PCT 8 [0079] FIG.30 shows a side perspective view of an interlocking toe box and shank of FIG.25 in plantar flexion. DETAILED DESCRIPTION [0080] Representative embodiments according to the inventive subject matter are shown in FIGS.1-30, wherein the same or generally similar features sharing common reference numerals. [0081] The inventive subject matter is generally directed to shoes that provide a foot conforming fit and support through a range of foot flexions, including those that correspond to the demi pointe, en pointe, and tendu positions. The inventive subject matter provides a system to support the intended wearer's foot and inhibit over plantar flexion, while not inhibiting dorsiflexion foot. [0082] Dance shoes, particularly those intended for ballet, jazz dancing, character dancing, and ballroom dancing may embody the inventive subject matter. Often, such shoes include a distal part that has a rigid section for supporting and protecting an intended user's forefoot during plantar flexion. Pointe shoes, for example, have a distal part in the form of a rigid toe box that encases at least the toes of a dancer (i.e., the toe box surrounds at least the sides, top and front of the toes, as is well known in the art of pointe shoes). The toe box provides support and helps protect a dancer's foot en pointe. The distal part is coupled to a proximal part that is configured for receiving midfoot to rearfoot portions of the foot. In conventional pointe shoes, the proximal part includes a rigid shank that structurally couples with the toe box. However, while the shank/toe box support the foot en pointe, they do not adequately flex with and conform to the foot as it leaves plantar flexion and goes into dorsiflexion. [0083] To overcome such disadvantages, the proximal part includes a structure with selected and directionally controllable rigidity. The structure may be in the form of a board or a resilient plate structure. The board or plate may be structurally coupled to the distal part. For example, it can be a separate element affixed to the distal part or it may be a portion of a unitary structure with the distal part. In any case, the structure is designed to flex with the foot as it goes into dorsiflexion. But it can also flex with the foot as it goes into plantar flexion. To inhibit the foot from over plantar flexion, in some embodiments, the structure includes at least one unidirectional stop that inhibits the structure from bending beyond a desired degree of plantar flexion. Thereby, the structure helps support the foot through that degree of plantar flexion and inhibits the foot from going beyond it. The structure therefore provides the functionality of both a rigid shank and a flexible sole in a single unit. A structure that serves such functions may be referred to herein as a “sole shank”. [0084] FIGS.1-5 show one possible embodiment of a sole shank that may be used with the inventive subject matter. FIGS.1A-1B show, respectively, bottom and top views of a sole Atty. Docket No.: BCH2039PCT 9 shank 50 with unidirectional flex capability. In this example, the sole shank has a multilayer, laminate construction of varying materials. FIG.2 shows an exploded view of the sole shank of FIG.1A. FIGS.3B-3D show side elevations of the sole shank in, respectively, dorsiflexion, neutral and plantar flexion configurations. FIG.3A shows human feet in footwear in the dorsiflexion position, illustrating how the sole shank can flex with and conform to a foot in that position. Similarly, FIG.4A shows sole shank 50 in a plantar flexion configuration. FIG. 4B shows a human foot in footwear in the plantar flexion (en pointe) position, illustrating how the sole shank can conform to and support a foot in the position. FIG.5 shows a cutaway of a dance shoe, such as a pointe shoe, incorporating a sole shank in an underfoot portion. [0085] Per certain embodiments of the inventive subject matter, the sole shank has one or more unidirectional stops 60 in the distal part corresponding to the forefoot region, as shown in FIG. 6B and FIG.8. The unidirectional stop may be configured as one or more living hinges. Generally, as used herein, a living hinge is a flexible bearing formed in the surface of a substrate structure and is generally made from the same material, or composite of material layers, as the two relatively rigid sections connected on either side of the hinge. The substrate material for the living hinge is typically thinned or cut along a predetermined line (linear or nonlinear) to allow the interconnected sections to bend or rotate along the line. [0086] In some embodiments of the inventive subject matter, a living hinge may be formed in one or more layers of material making up the sole shank structure. In general, a living hinge is a groove or channel with sidewalls that are separated by a small gap, or the walls may be in contact but separable. Those walls converge into a closed bottom. The closed bottom may be a floor (i.e., a generally horizontal surface) or an apex. The hinge is disposed in the ground-facing side surface of the sole shank structure, extending generally laterally through the surface. [0087] The opposing walls W₁, W₂ of a living hinge may converge to a bottom b in the form of a floor or an apex in any of various ways. The walls and floor may have, for instance, a U-shape, a V-shape, or various other shapes representing a recessed area. As another example, a groove or channel of a living hinge may have more than two walls/floor, as in an accordion shape, with more than three or more walls in alternating angles. The walls in any living hinge may therefore be parallel or angled as they converge to a flat or radiused floor or to an apex. They may also be linear or nonlinear. For example, they could be straight or have a convex or concave form. [0088] When the sole shank is in a neutral position (its default, unweighted or unstressed form), the walls, W1, W2, may be closely adjacent and even in close contact but separable. Or they be separated by a predetermined amount. In some embodiments, suitable gaps at the top of the walls may be from 0.7 mm to 1 mm, or thereabout. The groove or channel defining a line of flex may be a continuous structure that runs a predetermined length in a structure to define the line of flex. Atty. Docket No.: BCH2039PCT 10 Or the line of flex may have a discontinuous groove or channel where the line of flex is defined by depressions in the surface material separated by apertures (i.e., through holes) in the substrate material(s). Think of a row of alternating dashes and dots: the dashes represent depressions in a substrate material's surface; and the dots represent apertures that separate the dashes. The line of depressions and apertures therefore can act as a living hinge based on the overall weakening of the substrate along such line. Again, such line may be considered a discontinuous groove or channel. In such a structure, the attributes of the depressions and apertures may be varied in any number of ways to control flex, including by varying their shapes and dimensions. [0089] To selectively control rigidity/flex in a sole shank, the depth of continuous or discontinuous grooves or channels in substrate material(s) may vary. For example, relatively deeper grooves or channels will be relatively more flexible than shallower grooves or channels in the same substrate. In suitable embodiments, the grooves or channels may be formed with a depth sufficient to create a flexural line. In typical applications, it is expected that a sufficient depth will be at least 0.5 mm into the depth of the substrate structure from its surface. The maximum depth can be 100%. In other words, a substrate material can be cut through and fastened to an adjacent plate or board that is continuous below the cut-through segments. The segments could be fastened in any way that materials can be fastened, including by chemical bonding using adhesives, or by fusing of materials, or by mechanical fasteners. [0090] In any given groove or channel, the depth may be uniform, or it may vary across its length. For example, varying the depth may provide more less flexing on one side of the sole shank versus the other. Such variations may also be made from row-to-row in a set of living hinges. [0091] The unidirectional stop in a living hinge may be based on the abutment of the opposing vertical walls. The opposing walls may be separated in the neutral position and may separate further as the sole shank flexes from a neutral position into dorsiflexion (FIGS.3C and 3B), allowing the sole shank to dorsiflex with the foot. The opposing walls converge into abutment as the sole shank goes from a neutral position (FIG.3c) into plantar flexion (FIG.3D), allowing the sole shank to lock and support the foot during plantar flexion, including en pointe and tendu positions. In the embodiment of FIGS.1-5, a plurality of generally parallel rows of living hinges with unidirectional stops are formed in a forefoot portion of the sole shank. In this embodiment, the hinges are disposed primarily under the ball of the intended user's foot. By spacing the living hinges over the forefoot area shown, the hinges collectively allow the sole shank to follow the dorsiflexion of that part of the foot but lock as the foot goes through plantar flexion. [0092] In the embodiment shown, the living hinges 60 have a non-linear form or configuration in or over the surface of the sole shank. Advantageously, a non-linear form increases the surface Atty. Docket No.: BCH2039PCT 11 area of abutting walls in the living hinges for a stronger support system. More particularly, the living hinges in the embodiment shown have a curving form, e.g., a wavy, undulating form, as they extend laterally over the sole shank. The curving, wavy lines maximize wall surface area across the width of the sole shank and allow for smoother mechanical engagement and disengagement. The curving form also helps reduce wear in the hinges by avoiding sharp corners that would suffer higher engagement force on abutment. [0093] The undulating form has a plurality of minima M_n and maxima M_x (collectively known as extrema) across the width. The extrema spaced generally across the width of the sole shank in each of a plurality of rows. For many applications, from 1-3 extrema per row will be suitable. The number of extrema may be the same or vary from one row to another. For example, a wider portion of the sole shank may have more extrema compared to a narrower area. In the embodiment shown in FIGS.1-5, central minima are disposed at the center of the sole shank or thereabouts. Lateral maxima are disposed on either side of each central maxima for a total of three extrema in each row. [0094] As used herein, an undulating form may be not only a curvaceous waveform, but it also may be a zigzag or square wave form, or any of various other such forms of cycling. The extrema in an undulating form may have uniform wavelength and amplitude across a given row or from one row to another. For instance, in the embodiment shown, the central minima in each row have longer wavelengths than the adjacent maxima. However, in other embodiments, the extrema may have the same wavelengths to make a uniform distribution of extrema. Further, the waveform pattern in one row can differ from any other row. In the example of FIGS.1-5, each row has substantially the same wave form pattern. Suitable wavelengths may range from 5 cm to 7 cm, or thereabout, and suitable amplitudes may range from 0.7 cm to 1 cm, or thereabout [0095] As indicated, the living hinge may be formed in a single body of material or through multiple laminated layers of the same or different material, which together form a unitary structure. Living hinges could be formed in a substrate by laser cutting, mechanical grooving, chemical ablation, and any other known techniques for forming recessed areas in a substrate's surface. [0096] In addition to living hinges, the unidirectional stop used in a flex line may take other forms. A hinge could be any bridging of opposing sole-shank sections that provides a line for unidirectional bending or rotation of the interconnected sections. For example, well-known pin- coupled hinge systems with unidirectional stops, like those used in doors and cabinetry could be used to bridge opposing sections of a sole shank. Such known systems could be scaled down and adapted for use in a sole shank. Another possibility is a thin, flexible structure, e.g., a flexible Atty. Docket No.: BCH2039PCT 12 plastic strip, which interconnects opposing sections of a sole shank. Such a system provides a composite living hinge. [0097] Looking at the sole shank of FIGS.1-5, sole shank 50 is a unitary structure with multiple layers, 51-54, of the same or different materials. The layers may be affixed to each other through known means like mechanical or adhesive bonding. They may also be formed as different layers of molded polymer material. For example, such layering may be formed using known comolding or overmolding processes. Moving along the sole shank's longitudinal line, the number of layers and/or properties in a given layer in the laminated composite structure may be uniform. Alternatively, they may vary to provide selectively tuned sections, with varying support and flexibility attributes. [0098] For example, in FIG.1A, the sole shank is defined in terms of a plurality of zones Z1-Z4, which represent sections where stiffness or flexibility varies from one section to another. Variations may be achieved by differing, for example, the durometer, thickness, or structural features of one zone relative to another. An example of structural variation would be the differing possible continuous and discontinuous living hinges detailed earlier. [0099] In the sole shank shown, top layer 51 includes a relatively rigid, full-length fiber board, made of fibers and adhesives. The top layer serves as a foot-supporting element and is tuned to provide a balance of rigidity and flexibility to achieve the objectives of the sole shank. One suitable fiber board, well known in the art, is “Redboard”. Redboard is a man-made fiber board of fiber and adhesive. It is relatively stiff when provided in thicknesses sufficient to support the foot en pointe. While it can support the user's foot in an appropriate thickness (i.e., an individual layer or laminated layers), the support is provided at the cost of flexibility, with dorsiflexion being impeded in dance shoes. [0100] Accordingly, under the inventive subject matter, layer 51 may not be provided in a thickness that is overly rigid, and hinges may be provided in other layers, as discussed below, to improve the flexibility of the overall sole shank while providing needed rigidity. Other relatively rigid boards, which are functionally like Redboard, may be used as top layer 51. For example, there are various known rigid boards made of fibers, leather, metal, polymers, or combinations of such materials. [0101] Although the top layer is shown as a full-length unit, it may have varying lengths. For example, it could be a ¾ or ½ length board extending partially towards the end of the rearfoot. Although not shown, the top layer may not be the topmost layer in a shoe. For instance, a comfort liner, or cushiony insole may be disposed in a foot compartment above layer 51. [0102] Below and adjacent top layer 51 is intermediate layer 52. This layer may be a leather board. It may be full length, as shown, or partial length like the top layer. This layer is relatively Atty. Docket No.: BCH2039PCT 13 flexible and may serve to interconnect and stabilize stiffer layers above and below it. In addition to natural leather, layer 52 may be a synthetic leather or a durable textile material. [0103] Below and adjacent the intermediate layer 52 is another intermediate layer 53. This layer may be made of Texon board, a cellulosic fiber board. It is shown disposed in a midfoot-rearfoot section of the sole shank. It helps provide functional cohesiveness to the overall sole shank, allowing the other layers of the sole shank to bend without separating. [0104] Finally, in this example, adjacent and below the intermediate layer 53 is a bottom layer 54. The bottom layer may be full length or partial length. In this case, it is a partial length layer that extends from the distal end of the forefoot to about the distal-most side of the rearfoot or to about the proximal-most side of the midfoot. The bottom layer leaves the intermediate layers partially exposed on the bottom side in the proximal midfoot to rearfoot sections of the sole shank. The bottom layer is a relatively stiff layer that provides substantial support to the foot en pointe. The other layers may be relatively less rigid standing apart from the bottom layer. The addition of the bottom layer stiffens the overall structure of the sole shank so that it is suitable for supporting the foot en pointe and in other plantar flexions. However, to provide for needed dorsiflexion, living hinges 60 are disposed only in the forefoot section of bottom layer 54, section Z2. Section Z2 is disposed behind a relatively less flexible distal forefoot section Zi. That section may be part of a rigid toe enclosure, such as a toe box. Because it has hinges, section Z2 unidirectionally flexes with the intended user's foot during dorsiflexion but locks the sole shank as the user's foot moves into plantar flexion. In this embodiment layer 54 is the substrate material for the hinges. The hinges may be formed partially or fully through the surface layer 55. If formed fully through, the cut segments of layer 55 may be bonded to adjacent intermediate layer 52, with walls Wi and W2 formed in bottom layer 54 and the surface of intermediate layer 52 serving as bottom b. [0105] The bottom layer 54 has a generally tear-drop shape, tapering into a narrow shank as it extends towards the rearfoot. This shape supports the foot across midfoot Z₃, which is relatively stiff compared to rearfoot section Z4, because section Z3 consists for three layers and section Z4 consists of two layers or three layers, with layer 53 being relatively flexible. [0106] It should be appreciated that the foregoing embodiment is not intended to be scope limiting. It is merely an example within the broader scope of the inventive subject matter. Many variations are possible. For example, multiple layers could be provided in the form of single layer that provides the same general functionality. Layers may be varied in lengths and positions in the overall sole shank and with respect to each other. Other variations are possible, as well, with any variation serving a common general object of providing a sole shank that affords (1) Atty. Docket No.: BCH2039PCT 14 preferential dorsiflexion in a first direction, and (2) stiffening in an opposing direction, for plantar flexion and foot support. [0107] In any of the embodiments contemplated herein, the dance shoe has a foot-receiving compartment 10 that covers some or all the top of the user's foot. A sole unit, namely a structure that under the user’s foot and suitable for ground contact, is disposed on the bottom portion of the compartment. Often, compartment 10 is as full-length covering that is formed of a distal part 12, an intermediate part 13, and a proximal part 14. Distal part 12 of foot-receiving compartment 10 generally corresponds to a forefoot region of a foot. It is configured to receive at least a portion of a forefoot of the intended wearer's foot. Intermediate part 13 generally corresponds to a midfoot region of a foot. It is configured to receive at least a portion of a midfoot of the intended wearer. Proximal part 14 of foot-receiving compartment 10 generally corresponds to a rearfoot region of a foot. It is configured for receiving at least a rearfoot region of the foot. The intermediate part 13 is coupled to both the distal part 12 and the proximal part 14. They may be attached as separate pieces or formed as a unitary piece. [0108] The foot-receiving compartment 10 generally consists of a shoe upper 44 that is attached to a sole unit 40 disposed on the bottom side of the shoe. The sole unit may be a full-length sole unit or a partial sole unit, e.g., just forefoot and rearfoot sole. Seams may be used to join portions of fabric. The upper may be a full or partial encasing for the foot. For example, it may have portions that encase the sides and top of the foot and connect to a sole unit that forms a bottom portion of the shoe. Or, it may include a bottom portion connected to the side portions, creating a sock-like structure, for fully encasing the foot, for instance, with the bottom portion connecting directly or indirectly to a sole unit such as an outsole or an assembly of a midsole and outsole. In certain applications, the non-toe-box part of the foot-receiving compartment, i.e., the midfoot and rearfoot portions, will be constructed of one or more thin, flexible plies of materials that can conform to the foot like the way a sock does. By comparison, for example, most athletic or work shoes have relatively bulky, non-conforming rubber or other molded-polymer outsoles and midsoles in the midfoot and rearfoot portions that prevent a sock-like fit. And their uppers may include relatively non-compliant portions such as natural and synthetic leathers, molded plastic sections, or plies of material that while flexible are not very compliant, i.e., they do not conform easily to the contour of a foot. In other embodiments, straps, mesh of perforated materials may be used in areas of the foot compartment instead of continuous sheet material. [0109] In dance shoes, the foot-receiving compartment 10 (excluding any rigid toe box structure) may be primarily made of supple, soft, and thin materials like a satin or satin-like textile material, canvas, leather, or various other such materials. In some embodiments, it may be made in whole or part of a single ply of thin, flexible material (except possibly for the toe box Atty. Docket No.: BCH2039PCT 15 structure, a thin comfort lining and/or an optional insole). In other embodiments, the foot- receiving compartment may be made of multiple plies of material, or a combination of single-ply and multi-ply materials. In some embodiments, the inside of the foot-receiving compartment 10 may be provided with a liner inside a ply of an outer-facing material, such as a ply of satin. [0110] In certain embodiments of the inventive subject matter, the distal part 12 of foot- receiving compartment 10 includes a rigid toe box 16 or other rigid compartmental portion that provides support for a dancer to stand or balance in demi and en pointe positions. In some embodiments, the pointe shoe may have pleats 18 at the front of the foot-receiving compartment 10, e.g., at front of toe box 16. Pleats are created when upper is folded into the bottom of the shoe underneath front sole. [0111] The sole unit 40 may be a structure that functions as an outsole and optionally a midsole and/or an insole. A sole shank may be incorporated into any layer of the sole unit, and it may form in whole or part any one or more of the outsole, midsole, or insole. The sole unit 40 can be selected and configured to provide any number of attributes, including traction or lack of traction (e.g., a smooth surface for spin moves), protection, and/or force dissipation or force return. A sole unit may be fashioned to have multiple attributes in a given zone of the foot. Similarly, a sole unit may be fashioned to have multiple zones, each with a unique set of attributes. [0112] As shown in the Figures, per some embodiments of the inventive subject matter, the sole unit 40 includes a sole shank, which is configured to extend longitudinally from the distal part 12 to the proximal part 14 of a shoe. [0113] The dimension of any sole shank may vary with respect to a sole unit 40. In one possible embodiment, as illustrated in FIGS.1-8, for example, the length of the sole shank is about equal to the full length of the sole unit (i.e., the length of the sole shank is at least greater than 0.85 L), such that the distal end of the sole shank is generally located under the toes, and the proximal end of the sole shank is generally located under the heel. In another embodiment, as illustrated in FIGS.9-10, the length of the sole shank is longer than half but shorter than full length of the sole unit. In one particular embodiment, the length of the sole shank is about equal to three- quarter length of the sole unit, i.e., the length of the sole shank is between 0.65 L-0.85 L. Yet in another embodiment, the length of the sole shank is about equal to the half-length of the sole unit, i.e., the length of the sole shank is between 0.4 L-0.65 L. [0114] FIG.6A shows the top view of a dance shoe having an alternative sole shank 150, which includes a single forefoot hinge 160 that runs across substantially the full width of the sole shank. However, such a shoe may be used with other embodiments, including sole shank 50 or 250. The shoe has a length of L, which is measured longitudinally between the Atty. Docket No.: BCH2039PCT 16 farthest points separating toe and heel. The width of the shoe, which is measured transversely, may vary along the longitudinal direction. For example, the midfoot region may be slightly narrower than the forefoot region and rearfoot region. The shoe is approximately symmetric about a central axis 20 in the longitudinal direction. [0115] In some embodiments, such as that of FIGS.1-8, the width of the sole shank is about equal to the width of the sole unit 40, i.e., the medial and lateral edges of the sole shank generally match respectively the medial and lateral boundaries of the sole unit. In other embodiments, as illustrated in FIGS.9-10, the width of the sole shank is substantially narrower than the width of the sole unit 40, wherein “substantially narrower” means that the width of the sole shank, at any point along the longitudinal direction, is less than half width of the sole unit. [0116] Generally, the sole shank is arranged along and over a central axis 20 in the longitudinal direction of the shoe. In certain embodiments, as shown in FIGS.9-10, the sole shank 250 may have a tapering form, such that its width is larger in the distal region and smaller in the proximal region. [0117] According to certain embodiments of the inventive subject matter, the sole shank includes a resilient board or plate structure that may extend in two or three dimensions. The resilient plate structure may have tuned flexibility, i.e., different areas of the resilient board or plate structure may have selectively different stuffiness or flexibility. [0118] In some embodiment, a resilient plate structure may be a fiber-reinforced plastic (FRP) plate. As known in the art, FRP is a composite material made of a polymer matrix reinforced with fibers. The fibers are usually glass, carbon, aramid, or basalt. Possibly, other fibers such as paper or wood or asbestos may be used. The polymer is usually an epoxy, vinylester or polyester thermosetting plastic, and phenol formaldehyde resins may also be used. [0119] A polymer is generally manufactured by step-growth polymerization or addition polymerization. When combined with various agents to enhance or in any way alter the material properties of polymers the result is referred to as a plastic. Composite plastics refer to those types of plastics that result from bonding two or more homogeneous materials with different material properties to derive a final product with certain desired material and mechanical properties. FRPs are a category of composite plastics that specifically use fiber materials to mechanically enhance the strength and elasticity of plastics. The original plastic material without fiber reinforcement is known as the matrix. The matrix is a tough but relatively weak plastic that is reinforced by stronger stiffer reinforcing filaments or fibers. The extent that strength and elasticity are enhanced in a FRP depends on the mechanical properties of both the fiber and matrix, their volume relative to one another, and the fiber length and orientation within the matrix. Reinforcement of the matrix occurs when the FRP material exhibits increased strength or Atty. Docket No.: BCH2039PCT 17 elasticity relative to the strength and elasticity of the matrix alone. FRP involves two distinct processes, the first is the process whereby the fibrous material is manufactured and formed, the second is the process whereby fibrous materials are bonded with the matrix during molding. [0120] Reinforcing fiber may be manufactured in both two-dimensional and three-dimensional orientations. Fiber preforms are how the fibers are manufactured before being bonded to the matrix. Fiber preforms are often manufactured in sheets, continuous mats, or as continuous filaments for spray applications. Some major ways to manufacture the fiber preform is through the textile processing techniques of weaving, knitting, braiding, and stitching. [0121] A rigid structure is usually used to establish the shape of FRP components. Parts can be laid up on a flat surface referred to as a “caul plate,” or on a cylindrical structure referred to as a “mandrel”. However, most FRP parts are created with a mold. Molds can be concave female molds, male molds, or the mold can completely enclose the part with a top and bottom mold. The molding processes of FRP begins by placing the fiber preform on or in the mold. The fiber preform can be dry fiber, or fiber that already contains a measured amount of resin called “prepreg”. Dry fiber is wetted with resin either by hand or the resin is injected into a closed mold. The part is then cured, leaving the matrix and fibers in the shape created by the mold. Heat and/or pressure are sometimes used to cure the resin and improve the quality of the final part. Some methods of forming include bladder molding, compression molding, autoclave/vacuum bag, mandrel wrapping, wet layup, chopper gun, filament winding, pultrusion, and resin transfer molding. [0122] The matrix must also meet certain requirements to first be suitable for FRPs and ensure a successful reinforcement of itself. The matrix must be able to properly saturate, and bond with the fibers within a suitable curing period. The matrix should preferably bond chemically with the fiber reinforcement for maximum adhesion. The matrix must also completely envelop the fibers to protect them from cuts and notches that would reduce their strength, and to transfer forces to the fibers. The fibers must also be kept separate from each other so that if failure occurs it is localized as much as possible, and if failure occurs the matrix must also de-bond from the fiber for similar reasons. Finally, the matrix should be of a plastic that remains chemically and physically stable during and after the reinforcement and molding processes. To be suitable as reinforcement material, fiber additives must increase the tensile strength and modulus of elasticity of the matrix and meet the following conditions; fibers must exceed critical fiber content; the strength and rigidity of fibers itself must exceed the strength and rigidity of the matrix alone; and there must be optimum bonding between fibers and matrix. [0123] One representative example of the FRP plate is carbon fiber plate. The plate is formed from a fiber preform, for example, the preform may be one or more layers of carbon fibers or Atty. Docket No.: BCH2039PCT 18 filaments. Carbon filaments in each layer may be arranged in varying density and/or weave pattern to give the carbon fiber plate varying strength-to-weight ratio and rigidity. The fiber preform may be resin impregnated. The properties of the plate, e.g., strength and rigidity, may be varied according to the type of fiber preform and matrix being used. [0124] In certain embodiments, an FRP plate shank may be affixed to or embedded within one or more boards or other layers of a sole unit 140 or a sole shank, which may be part of the sole unit or the upper. A board may be, but is not limited to, a leather board, a fiber board, a cellulose board, or a cardboard. For example, FIGS.9-10 show a sole unit 140 including a shank 250, which is made of a carbon fiber or other FRP plate, and which is affixed to a layer of thin, but relatively stiff, grey board 70. The grey board is disposed on top of another layer of relatively flexible leather board (not shown in FIG.9 but seen in the exploded view of FIG.10). The grey board has several laser-cut or mechanically formed lines 260, serving as living hinges, formed partially through its thickness in the forefoot region for facilitating flexibility in that region. [0125] In the various embodiments, a sole shank may be flat, or it may pre-shaped in three dimensions (e.g., by using a moldable material). For example, the sole shank may be pre-shaped in a plantar-flexed position near an arch portion 64 of the foot, as illustrated in FIG.8, for example. This may facilitate plantar flexion of the foot, e.g., when the dancer transitions to en pointe and tendu positions, as the sole shank 150 tends to return to its pre-shaped position. In addition, the shoe may be made on a last representing a pronounced plantar flexion. In certain embodiments, the plantar flexion corresponds to or mimics the shape of a foot when en pointe, for example the last may have a curved profile in mimicking the profile of a foot when en pointe, resulting in a shoe having a corresponding curvature. [0126] As known in the art, a last is a shaped, three-dimensional body corresponding to a size and shape of a model foot. Shoe parts, including those that form the foot-receiving compartment, are placed around the last form, and assembled together. Once assembled in the shape of the last, the last is removed. The sole unit may be assembled to the compartment while it is on the last. [0127] Per certain embodiments of the inventive subject matter, an example of which is seen in FIG.7B, a sole shank 150 has at least three zones Z1, Z2, Z3 of varying flexibility along its longitudinal axis, including a relatively stiff zone Z₁ located near a toe portion of the foot, a relatively flexible zone Z2 located near a ball portion of the foot, and a relatively stiff zone Z₃ located near an arch portion of the foot, which may have the same stiffness as Zi or may be more or less stiff. [0128] In one exemplary embodiment, as illustrated in FIG.7B and FIG.9, the sole shank 250 has four zones of varying flexibility along its longitudinal axis, including a stiff zone Z₁ located near a toe portion of the foot, a flexible zone Z₂ located near a ball portion of the foot, Atty. Docket No.: BCH2039PCT 19 a stiff zone Z3 located near an arch portion of the foot, and a flexible zone Z4 located near a rearfoot portion of the foot. (As in other examples, references to stiffness of one zone to another are relative determinations.) The stiff zones Z1, Z3 in the sole shank provide extra support for the toe portion and near the arch portion of the foot, particularly when the foot is in plantar flexion. The flexible zones Z2, Z4 in the sole shank allow sufficient flexibility of the foot movement during the dancing, e.g., facilitating the dorsiflexion of the foot. The flexible zone Z2 may also be adapted to be springy or bouncy to provide energy return to facilitate forefoot movement during dancing. [0129] As with other embodiments, an FRP sole shank with varying zones of stiffness based on differences in material property may also include a unidirectional stop in the form of a living hinge 160, which allows the sole shank to bend without breaking. The living hinge may be made, for example, from the same material layer or layers as it interconnects. For example, the living hinge could interconnect two sections of carbon fiber with different stiffness or flexibility. In one representative embodiment, the living hinge is formed along the boundary between the stiff zone Z₁ corresponding to the toe portion and the flexible zone Z₂ corresponding to the ball portion of the foot. [0130] Various methods may be used to create multiple zones of varying flexibility for the sole shank. Per one possible embodiment, this is achieved by at least varying the thickness of the sole shank, e.g., by employing different number of fiber layers, in different zones. In another embodiment, this is achieved by at least varying composition material of the sole shank in different zones, e.g., the stiffness or flexibility of a fiber preform may vary by changing its durometer, fiber density or thickness, thread count and/or tow size (i.e., number of filament fibers in a bundle). Yet in another embodiment, multiple zones of varying flexibility may be created by at least varying a weave pattern of an FRP or other woven sole shank in different zones. The weave pattern, including the orientation of individual fibers and how the fibers interlace with each other, may affect the stiffness or flexibility of a fiber plate. Some typical weave patterns include, but are not limited to, plain weave, twill weave, satin weave, etc. Custom defined weave patterns may also be used to create desired flexibility. [0131] Non-linear hinges with separated opposing walls, such as those shown in FIGS.1-3, may be readily formed in an exemplary sole shank, for example, by the molding process described above. In a board material, however, achieving such non-linear hinges with a laser cut or a mechanical cut is more challenging. Board material may be a more cost-effective material compared to molded plastic. Board material may provide technical advantages in a dance shoe compared to molded plastic. Atty. Docket No.: BCH2039PCT 20 [0132] Additionally, in some instances no matter the material, the opposing walls may engage and interfere with each other, for example, between the peaks and valleys of an undulating form. [0133] To address these problems, in some embodiments, the inventive subject matter is directed to a unidirectional hinge system that is readily formed in board and other stiff or rigid materials. The system wherein only selected first portions of a given hinge’s opposing walls abuttingly engage with one another as they move towards one another. Other second portions have opposing walls that remain separated when the opposing walls come into abutment. The second portions have greater gaps that then the first portions. [0134] FIG.12 illustrates a sole shank having a plurality of living hinges in a neutral position with hinges having alternating portions of varying opposing wall separation. The hinges maybe formed in a board material, molded plastic, or other material for a sole shank 350. Looking at hinges 360, each hinge 360 may include a pair of opposing walls, e.g., walls 362-1 and 362-2. The hinge 360 may be non-linear, e.g., undulating, or zigzag. The parts of the hinge between lines A and B, and between lines E and F, may be referred to herein as peaks or maxima, with the peaks or maxima distally oriented as seen in FIG.12, while the part of the hinge between the lines C and D may be referred to as a valley or a minimum. [0135] Each respective hinge 360 may include different portions. In a first portion, e.g., between lines B and C, or between lines D and E, the opposing walls are separated from each other by a first distance when the shank is in a neutral position. The first distance may be, for example, from 0.7 mm to 1 mm, or thereabout. The walls at the first portion may converge to abutment in plantar flexion. The first portion may correspond to an area between a peak and a valley in the overall form of the hinge. In other words, there are alternating peaks and valleys with the inflection points between each representing a point or section where opposing walls can abuttingly engage each other and thereby limit the plantar flexion of the sole shank. [0136] In a second portion, e.g., between lines A and B, between lines C and D, or between lines E and F, the opposing walls are separated from each other by a second distance, larger than the first distance, in the neutral position. The second distance may be, for example, from 2 mm to 6 mm, or thereabout. The opposing walls at the second portion remain separated from each other in plantar flexion. In other words, each peak and valley represents an open area with valleys generally being inverted peaks. [0137] This larger separation for the peaks and valleys, relative to the intermediate points or sections of inflection, may be achieved by removing a portion of the board material that contains the hinges 360. For example, a linear cut between lines A and B on a peak of the wall 362-1 may allow a piece of the board material above the cut to be removed, leaving a cut-out area 364. In Atty. Docket No.: BCH2039PCT 21 some examples, a curved cut, such as between lines D and D on a valley of the wall 362-2 and/or wall 362-1 may allow a piece of the board material to be removed, leaving a cut-out area 366. The cut-out areas may not extend completely through the entire thickness of the layer 354 and may include a floor or closed bottom. The depth of the cut-out areas may be the same as the depth of the hinges, shallower than the depth of the hinges, or deeper than the depth of the hinges. [0138] The cuts to create the hinges 360 and the cut-out areas 364, and 366, may be made, for example, with a laser cutting device, by a mechanical grooving or cutting apparatus, or by a combination of mechanical and laser cuts. Being able to form the hinges 360 as illustrated in a board material, instead of with molded plastic, may provide cost savings in materials, manufacturing processes, or both. Additionally, the cut-out areas separate opposing walls and thereby may reduce or prevent the opposing walls from engaging and interfering with each other during a transition from neutral to plantarflexion and/or dorsiflexion. [0139] As illustrated, the curvature of the opposing walls of a given hinge may define differing shapes for the cut-out spaces. For example, one of the opposing walls in the section between lines A and B, and between E and F, may have a linear, non-curved flat side below an opposing concave curve of the other of the opposing wall in that section. The opposing wall sections between lines C and D may both curve, with a first distal side opposing wall convexly curving and the second proximal side opposing wall concavely curving such that the first convexly curving side partially nests in the concavely curving side. The curvature of the opposing walls in the second portion is not limited to these examples. For example, instead of being curved, an opposing wall may be cut as two linear segments at an angle to each other, e.g., in a “V” shape as two sides of a triangle. [0140] FIG.13 illustrates an example of the layers that may form the sole shank 350. The sole shank 350 may include the bottom layer 354, an intermediate layer 352 and a top layer 351. In addition, a rigid toe box 316 may be affixed to the bottom layer 354 of sole shank 350. The layers 354, 352, and 351 may be analogous to the layers 54, 52, and 51, respectively. [0141] The rigid toe box 316 may include an aperture 319 over the central hinge (i.e., the part of the hinge between lines C and D). This aperture may permit more flexion of the under layers while the toe box resists lateral and/or medial twisting. The aperture may reduce the amount of material, and thus the weight, of the toe box. It optionally may also be used to receive an interlock that interlocks the sole shank with the toe box, as described in more detail below. HYBRID TOE BOX AND SHANK ASSEMBLIES [0142] Conventionally, pointe shoe construction may involve the use of multiple layered materials, bonded together using a combination of various types of adhesives. The shoes are Atty. Docket No.: BCH2039PCT 22 molded into shape to form the toe box compartment and heated to become rigid enough to support a dancer’s weight at the metatarsals while in the “en pointe” position. The insole or shank of conventional pointe shoes are made with a combination of organic materials, such as leather or fiber board, bonded together with various adhesive and small tacks. The insole/shank work in conjunction with the toe box to assist in supporting the dancer’s weight while “en pointe”. Conventional construction of pointe shoes is accordingly time-consuming, and the resulting shoe is subject to degradation after only a few uses by a dancer. [0143] Some attempts to improve on the conventional pointe shoe have included using an injected thermoplastic for the toe box and shank assembly. This approach, however, results in a pointe shoe with a unitary strength and flexibility for the toe box and the shank. Many dancers need a more rigid toe box and a more flexible shank, which cannot be achieved with a one-piece thermoplastic integrated toe box and shank. [0144] Accordingly, some embodiments may include a hybrid assembly of a toe box and shank. A hybrid assembly may include a polymer toe box and a shank made of a different material or materials. In some embodiments, an interlocking component may be provided to couple and lock the shank to the interlocking toe box. The hybrid assembly may allow different interlocking toe boxes and shanks to be combined to produce a dance shoe customized to the needs of an individual wearer. [0145] In some embodiments, a toe box may include one or more living hinges in an underfoot portion that permit the toe box to curve in dorsiflexion. In some embodiments, the hinges are formed in a toe box made of a thermoplastic or other moldable polymer. The living hinges may also be arranged like those in the sole shank to lock and support plantar flexion. The various embodiments of the hybrid or interlocking toe box may permit a greater range of motion to the wearer’s feet while still providing the rigid support needed during en pointe movements, increasing comfort, and decreasing injury and strain. [0146] FIG.14 shows a top view of an example of a toe box 416. The toe box 416 may include a flat exterior distal surface 418 that faces forward when the intended wearer’s foot is in a neutral position, and faces and contacts the floor when the intended wearer is en pointe. The toe box 416 may have a top side 417 and two opposing sides 415a and 415b. The bottom 420 of the toe box 416 may include an aperture 419 devoid of toe box material. [0147] As seen in FIG.15, the toe box 416 may be operationally coupled at an inner and/or outer surface to a shank or to a sole unit440, which may include a shank. For example, the sole unit 440 may be affixed to an inner surface of a bottom side, or sole portion, of the toe box 416. The sole unit may overlap the inner surface of the sole portion of the toe box fully or partially and extends rearwardly from the toe box, typically at least across the midfoot region to the rearfoot Atty. Docket No.: BCH2039PCT 23 region of the shoe, in the bottom, foot-supporting portion of the shoe. The toe box and shank or sole components may be operationally coupled or interlocked using various mechanical systems, including, for example, complementary male-female parts that snap fit or interference fit together as will be described further below. [0148] FIG.16 shows a bottom view of an example of a coupled toe box and sole shank assembly. A forefoot portion of the sole unit 440 may extend across the entire bottom side 420 of the toe box 416, e.g., across the width of the bottom 420 between the sides 415a and 415b. [0149] The toe box 416 may include one or more living hinges 460 disposed widthwise on either side of the aperture 419 across the area corresponding to the ball of the foot and a proximal portion of the toes of the intended wearer. As shown, the living hinges 460 may be straight, parallel flexural lines cut or formed in the material of the interlocking toe box 416. A pair of collinear hinges 460 may form one flexural line. For example, hinge 460a and hinge 460b may form one flexural line where the interlocking toe box 416 may flex. In the illustrated embodiment, the hinges 460 are offset from, and do not align with, the hinges 360 in the sole shank. [0150] FIG.17 shows a first side view of a coupled toe box and sole shank assembly with a visible bottom side 420. FIG.18 shows a second side view of the toe box and sole shank assembly with a visible top side 417. In the illustrated embodiment, the edges of the sides 415a and 415b may be angled between the top side 417 and the bottom side 420, where the angle between the edges of the sides and the bottom side is not perpendicular. In other embodiments, the side edges may be perpendicular to the bottom side. [0151] FIG.19 shows a front view of the toe box 416 where the flat exterior distal surface 418 is visible. In the illustrated embodiments, the sides 415 and top 417 may be generally arcuate and may define one continuous curve from a lateral side of the bottom 420 to a medial side of the bottom 420. In other embodiments, the sides and/or the top may be a planar structure that meets an adjacent respective top or side at a corner rather than a curve. [0152] FIG.20 shows a bottom view of a second example of a coupled toe box and sole shank assembly. The bottom of the interlocking toe box 516 includes an aperture 519 devoid of toe box material. The interlocking toe box 516 includes a plurality of non-linear living hinges 560 disposed on either side of the aperture 519. In the illustrated embodiment, the hinges 560 may be aligned with and overlay the undulating hinges 360 such that the bottom of the interlocking toe box 516 flexes at the same points as the underlying sole shank. [0153] FIG.21 shows a bottom view of a third example of a coupled toe box and sole shank assembly. In the illustrated embodiment, the interlocking toe box 516 may be coupled to a shank 374 that has linear hinges 362, rather than non-linear undulating hinges. The hinges 560 may be Atty. Docket No.: BCH2039PCT 24 offset from the hinges 362. The number of flexural lines formed by the hinges 560 may differ from the number of flexural lines formed by the hinges 362. [0154] The embodiments are not limited to the illustrated examples. Other combinations of hinges on the sole shank and on the bottom surface of the interlocking toe box are possible. For example, the hinges on both the sole shank and on the toe box may be linear, and may be collinear or offset. [0155] FIG.22 shows a bottom view of a coupled toe box 616. The bottom of the interlocking toe box 616 does not include an aperture. The bottom of the toe box 616 may include one or more living hinges 660. In the illustrated example, the hinges 660 are linear and parallel and are disposed across the width of the forefoot of the shoe and cover an area under the ball of the foot and at least a proximal part of the toes of the intended wearer. The underlying shank layer 384 may include living hinges (not shown) as in any of the previous examples. In other embodiments, the underlying shank layer 384 may not include living hinges. [0156] FIG.23 shows a bottom view of a coupled toe box 716. The bottom of the interlocking toe box 716 does not include an aperture. The bottom of the toe box 716 may include one or more living hinges 760. In the illustrated example, the hinges 760 are non-linear and are disposed across the width of the forefoot of the shoe. The hinges 760 cover an area under the ball of the foot and at least a proximal part of the toes of the intended wearer. The underlying shank layer 384 may include living hinges (not shown) as in any of the previous examples. In other embodiments, the underlying shank layer 384 may not include living hinges. [0157] The toe boxes of any of the preceding embodiments may be made of thermoset or thermoplastic polymer, for example, an elastomeric thermoset compound (TPEE) or other plastic materials. The toe box material may be generally stiff to support the dancer’s foot while en pointe without collapsing. The toe box material may have some slight flexibility in dimensions tangential to the en pointe support, e.g., the sides of the toe box may be flexed slightly if the top and bottom of the toe box are pressed toward each other. Differing degrees of flexibility may be formed by varying a thickness of the material in different parts of the toe box. The polymer material for the toe box may be, for example, molded (e.g., injection molding), 3D printed, or cut or carved from a suitable material. [0158] The shanks coupled to the toe boxes of any of the preceding embodiments may be made of materials such as, but not limited to, leather, fiber board, fiber-reinforced plastic, molded plastic, or other material. [0159] FIG.24 shows an example of a shank, or insole, 800 that may be used with a toe box. The shank 800 may include an interlock or locking component 810. The locking component 810 may be made from the same material or materials as the shank 800 or from different materials. Atty. Docket No.: BCH2039PCT 25 The locking component 810 may be affixed to the shank 800 on the bottom side of the shank. The locking component 810 may be, for example, glued or bonded to the shank 800. The shape of the perimeter of the locking component 810 may be complementary to, i.e., conform with, the outline of an aperture in the toe box. Accordingly, the locking component 810, which may be considered a male part, may be configured to engagingly fit within a complementary aperture, a female part, of the toe box to lock the two components together. The aperture may be a through hole or a blind recess. Although single engageable locking elements are shown, a toe box and shank or other part may each have multiple engageable parts that lockingly engage with complementary elements on another part. For example, the engagement of parts may be like a snap fit, with pressure and/or friction keeping the parts in engagement. Advantageously, the engageable parts may be removably engageable so parts can be traded out to create various combinations for toe boxes and shanks or other parts. For example, varying arrangements may provide for varying flexibility or stiffness, or for replacement of worn parts, or for varying sizing. [0160] The interlock of toe box and shank or sole components may be achieved using various mechanical systems, including complementary male-female parts that snap fit or interference fit together. For example, a system of ridges on the bottom surface of the shank (or the interior surface of the bottom of the toe box, may be insertable into a system of grooves disposed on the interior surface of the toe box (or on the bottom surface of the shank) to interconnect the two components. In another example, a plurality of smaller protruding locking elements may snap into a plurality of smaller female apertures or recesses. In another example, a plurality of protruding mushroom-shaped locking elements, e.g., DUAL-LOCK by 3M, may be disposed on both the interior surface of the toe box and on the bottom surface of the shank and may interlock. Further, while the locking component is depicted here as protruding from the bottom surface of the shank to be interlocked with an aperture in the toe box, in other embodiments, the locking component may protrude from the interior bottom side of the toe box to be interlocked with an aperture in the shank. [0161] FIG.25 shows a bottom view of the shank 800 locked into an aperture 819 of toe box 818. The locking component 810 is visible through the aperture 819 of the interlocking toe box. In some embodiments, a secondary mechanical lock, such as a tack 820, may couple the proximal end of the interlocking toe box 818 to the shank 800. [0162] FIG.26 shows a perspective bottom view of a partially disassembled shank and interlocking toe box system. Specifically, the locking component 810 is shown removed from the shank 800. An adhesive 824 may be applied to the shank 800 in the area corresponding to the aperture in the toe box, between the distal end 819a and the proximal end 819b of the aperture. Atty. Docket No.: BCH2039PCT 26 The locking component 810 may also, or alternatively, be affixed to the shank with one or more secondary mechanical locks 822, such as tacks or rivets. [0163] FIG.27 shows a perspective top exploded view of the shank and coupled toe box system. The top surface 840 of the shank, i.e., the foot-facing surface, may be smooth. The locking component 810, when affixed to the bottom surface of the shank 800, may protrude from the bottom surface. [0164] FIG.28 shows a view of the interlocking toe box in simulated dorsiflexion. The distal end 830 of the bottom portion of the toe box may flex to a greater degree than the proximal forefoot portion 832 to accommodate the natural dorsiflexion of the intended wearer’s foot. The hinges 860 may nonetheless provide some degree of flexion in the forefoot portion, compared to a conventional rigid toe box, for example, during a transition to the en pointe position. [0165] FIG.29 shows a side view of an interlocking toe box and shank in simulated dorsiflexion. While on a flat surface, e.g., the floor, the proximal forefoot portion 832 may remain generally flat, while the distal end 830 of the toe box may flex as shown. The shank 800, coupled to the interlocking toe box, may also flex to conform to the intended wearer’s foot, causing the distal end of the interlocking toe box to flex. [0166] FIG.30 shows a view of the toe box and shank assembly in simulated plantar flexion. The shank 800, in conjunction with the coupled toe box, may provide rigid stability to the intended wearer’s foot while in planar flexion, i.e., in the en pointe position. [0167] The combination of the toe box and tuned sole shank may accordingly provide a dance shoe with the structural rigidity and support for a dancer's foot in the en pointe position, and the flexibility to flex the foot in other dance movements and during the transitions in and out of en pointe. Further, the combination of the toe box and tuned sole shank may provide these benefits without the prolonged breaking-in period required by conventional toe shoes while improving durability and the useful life of a toe shoe. TERMINOLOGY AND SCOPE [0168] As used herein, a “plantar flexion” of the foot refers to the downward movement of the foot and toes which increases the approximate 90-degree angle between the front part of the foot and the shin at the neutral position (i.e., foot is flat). A “dorsiflexion” of the foot refers to the upward movement of the foot and toes which decreases the approximate 90-degree angle between the front part of the foot and the shin at the neutral position (i.e., foot is flat). [0169] FIG.11 is an anatomical mapping of the foot. The “forefoot” includes the toes and metatarsals, and it provides the ground contact area of the ball of the foot. It consists of most of the bony architecture of the foot including phalanges to the toes, five metatarsal bones and the Atty. Docket No.: BCH2039PCT 27 two sesamoid bones of the big toe joint. The “midfoot” is the intersection between the forefoot and rearfoot. Its anatomic location is at the peak or highest part of the arch and has important joints connecting it to the forefoot and the rearfoot region. It consists of five bones including three cuneiform bones, and the navicular and cuboid bones. The “rearfoot” connects to the midfoot and to the ankle and provides the ground contact area of the heel region of the foot. It consists of the bony architecture of the calcaneus and talus. [0170] Accordingly, in the inventive shoes, the “forefoot region” of the compartment refers generally to a portion of the compartment receiving the toes as well as the metatarsals of the foot of a wearer. The “midfoot region” of the compartment refers generally to a portion of the compartment receiving the arch of the foot of a wearer. The “rearfoot region” of the compartment refers generally to a portion of the compartment receiving the heel of the wearer. [0171] Persons skilled in the art will recognize that many modifications and variations are possible in the details, materials, and arrangements of the parts and actions which have been described and illustrated to explain the nature of the inventive subject matter, and that such modifications and variations do not depart from the spirit and scope of the teachings and claims contained therein. [0172] The principles described above about any particular example can be combined with the principles described in connection with any one or more of the other examples. Accordingly, this detailed description shall not be construed in a limiting sense, and following a review of this disclosure, those of ordinary skill in the art will appreciate the wide variety of systems that can be devised using the various concepts described herein. Moreover, those of ordinary skill in the art will appreciate that the exemplary embodiments disclosed herein can be adapted to various configurations without departing from the disclosed principles. [0173] The previous description of the disclosed embodiments is provided to enable any person skilled in the art to make or use the disclosed innovations. Various modifications to those embodiments will be plain to those skilled in the art, and the generic principles defined herein may be applied to other embodiments without departing from the spirit or scope of this disclosure. Thus, the claimed inventions are not intended to be limited to the embodiments shown herein, but are to be accorded the full scope consistent with the language of the claims, wherein reference to an element in the singular, such as by use of the article “a” or “an” is not intended to mean “one and only one” unless specifically so stated, but rather “one or more”. [0174] As used herein the terms “part”, “portion”, and “section” are generally synonymous terms and do not imply that something is or is not a discrete element or subcomponent in a larger construct or is or is not a non-discrete subdivision of a larger unitary construct, unless context indicates otherwise. Atty. Docket No.: BCH2039PCT 28 [0175] All structural and functional equivalents to the elements of the various embodiments described throughout the disclosure that are known or later come to be known to those of ordinary skill in the art are intended to be encompassed by the features described and claimed herein. Moreover, nothing disclosed herein is intended to be dedicated to the public regardless of whether such disclosure is explicitly recited in the claims. [0176] The inventor reserves all rights to the subject matter disclosed herein, including the right to claim all that comes within the scope and spirit of the following claims: Atty. Docket No.: BCH2039PCT 29

Claims

Listing of Claims: 1. A dance shoe having an upper and an underfoot portion, the underfoot portion including a sole shank, comprising: a stiffening structure, extending longitudinally in the shoe over at least a forefoot portion of the shoe and at least partially over a midfoot portion; a plurality of hinges, each with a unidirectional stop being disposed widthwise in the sole shank in at least the forefoot portion so that a forefoot portion of the sole shank locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of the foot and follow dorsiflexion of an intended wearer’s forefoot, wherein each hinge comprises a pair of opposing walls that have one or more first opposing-wall portions that that are spaced apart in a neutral, first position and are convergeable to abutment when moving from the neutral position to a second position representing a selected degree of plantar flexion, and (2) one or more second portion opposing-wall portions where the opposing walls are separated from each other in the neutral position and remain separated from each other in the selected degree of plantar flexion; and a rigid distal part of the shoe coupled to the sole shank.

2. The dance shoe of claim 1, wherein the rigid distal part comprises a rigid toe box.

3. The dance shoe of claim 1, wherein the hinges are disposed widthwise and without intersecting one another.

4. The dance shoe of claim 2 or any other claim herein, wherein first opposing-wall portions are inflection points or sections between second portion opposing-wall portions.

5. The dance shoe of claim 2, wherein there are three or more living hinges each with an undulating form.

6. The dance shoe of claim 5, wherein the length of the sole shank is about equal to the full length of the sole unit.

7. The dance shoe of claim 2, wherein the length of the sole shank is longer than half but shorter than full length of the sole unit. Atty. Docket No.: BCH2039PCT 30

8. The dance shoe of claim 7, wherein the width of the sole shank is about equal to the width of a sole unit in the dance shoe.

9. The dance shoe of claim 3, wherein the width of the sole shank is substantially narrower than the width of the sole unit, and the sole shank is disposed substantially on a central axis of the shoe.

10. The dance shoe of claim 3, wherein the sole shank is pre-shaped in a non-planar, three- dimensional form to facilitate plantar flexion of the intended wearer’s foot.

11. The dance shoe of claim 10, wherein the three-dimensional form represents an intended wearer’s foot in a plantar-flexed position, in particular a curved shape near an arch portion of the intended wearer’s foot.

12. The dance shoe of claim 1, wherein the opposing walls of a hinge have faces that are not parallel to each other and converge to a closed bottom.

13. The dance shoe of claim 1, wherein the opposing walls of a hinge have faces that are parallel to each other.

14. The dance shoe of claim 1, wherein the opposing walls of a hinges second portion corresponds to an area where some of the sole shank material is removed.

15. The dance shoe of claim 1, wherein the sole shank comprises a board material.

16. The dance shoe of claim 1, wherein, in the second portion, one of the opposing walls comprises a flat side below an opposing concave curve of the other of the opposing walls.

17. The dance shoe of claim 1, wherein, in the second portion, the opposing walls comprise a first distal side opposing wall convexly curving and a second proximal side opposing wall concavely curving such that the first convexly curving side partially nests in the concavely curving side.

18. The dance shoe of claim 1 or any other claim herein, wherein the opposing walls defining the first portion are separated by a first distance in the neutral position and the separation of the Atty. Docket No.: BCH2039PCT 31 opposing walls defining the second portion in the neutral position is larger than the first distance separating the walls in the first portion.

19. The dance shoe of claim 18, wherein first opposing-wall portions are inflection points or sections between second portion opposing-wall portions.

20. A sole shank comprising: a stiffening structure configured to extend longitudinally in a shoe over at least a forefoot portion of the shoe and at least partially over a midfoot portion, at least one hinge with a unidirectional stop being disposed widthwise in the sole shank in at least the forefoot portion so that the sole shank locks to support plantar flexion and hinges to facilitate dorsiflexion of the forefoot portion, the sole shank being coupled to a rigid distal part of the shoe, wherein each hinge comprises a pair of opposing walls defining a (1) first portion where the opposing walls are separated in a neutral position and are convergeable to abutment in a plantar flexion, and (2) a second portion where the opposing walls are separated from each other in a neutral position and remain separated from each other in the plantar flexion, and wherein the sole shank optionally is pre-shaped in a non-planar, three-dimensional form to mimic and thereby facilitate plantar flexion of the intended wearer’s foot.

21. A dance shoe, comprising: a distal part having a rigid toe box for encasing at least a portion of a forefoot of an intended wearer and supporting a foot of the intended wear; an intermediate part coupled to the distal part and configured for receiving at least a portion of a midfoot of the intended wearer; a proximal part coupled to the intermediate part and configured for receiving at least a rearfoot portion of the intended wearer; and a sole unit comprising a sole shank extending longitudinally from the distal part to the proximal part, wherein the sole shank has a plurality of hinges each with a unidirectional stop disposed widthwise in the sole shank in at least a forefoot portion that locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of the forefoot portion and follow dorsiflexion of an intended wearer’s forefoot, and wherein a portion of the sole shank in a midfoot position permits plantar flexion of an arch of the intended wearer’s foot, wherein each hinge comprises a pair of opposing walls defining (1) a first portion where the opposing walls are separated in a neutral position and are convergeable to abutment in plantar flexion, and (2) a Atty. Docket No.: BCH2039PCT 32 second portion where the opposing walls are separated from each other in the neutral position and remain separated from each other in the plantar flexion.

22. The dance shoe of claim 19, wherein the rigid toe box comprises an aperture positioned over a central portion of the sole shank configured to expose at least one of the second portions of the plurality of hinges.

23. A toe box for a dance shoe comprising: a hollow rigid structure comprising a bottom side, an opposing top side, a medial side and a lateral side disposed between the top side and the bottom side, and a flat front side coupled to each of the top side, bottom side, lateral side and medial side and enclosing a distal end of the hollow rigid structure; wherein the hollow rigid structure is configured to receive the toes and some or all of the rest of the forefoot of an intended wearer; and wherein an outer surface of the bottom side comprises a plurality of hinges, each with a unidirectional stop being disposed widthwise across the bottom side so that the bottom side locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of an intended wearer’s forefoot.

24. The toe box of claim 21, wherein the bottom side comprises a centrally disposed aperture between lateral and medial portions of the bottom side, the aperture being disposed over a majority of the length of a forefoot area of the bottom side.

25. The toe box of claim 24, wherein the hinges are disposed on the lateral and medial portions and are linear.

26. The toe box of claim 24, wherein the hinges are disposed on the lateral and medial portions and are non-linear.

27. A dance shoe, comprising: a toe box comprising a bottom side, an opposing top side, a medial side and a lateral side disposed between the top side and the bottom side, and a flat front side coupled to each of the top side, bottom side, lateral side and medial side and enclosing a distal end of the hollow rigid structure; Atty. Docket No.: BCH2039PCT 33 wherein an outer surface of the bottom side comprises a first plurality of hinges, each with a unidirectional stop being disposed widthwise across the bottom side so that the bottom side locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of an intended wearer’s forefoot; and a sole shank coupled to the bottom side of the toe box, comprising: a stiffening structure, extending longitudinally in the shoe over at least a forefoot portion of the shoe and at least partially over a midfoot portion, and a second plurality of hinges, each with a unidirectional stop being disposed widthwise in the sole shank in at least the forefoot portion so that a forefoot portion of the sole shank locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of the foot and follow dorsiflexion of an intended wearer’s forefoot, wherein a portion of the sole shank in a midfoot position permits plantar flexion of an arch of the intended wearer’s foot, the sole shank being coupled to a rigid distal part of the shoe.

28. The dance shoe of claim 25, wherein one of the first and second plurality of hinges is linear and the other of the first and second plurality of hinges is non-linear.

29. The dance shoe of claim 25, wherein the first and second plurality of hinges are linear.

30. The dance shoe of claim 27, wherein the first plurality of hinges is offset from the second plurality of hinges.

31. The dance shoe of claim 27, wherein the first plurality of hinges is collinear with the second plurality of hinges.

32. The dance shoe of claim 25, wherein the bottom side comprises a centrally disposed aperture between lateral and medial portions of the bottom side, the aperture being disposed over a majority of the length of a forefoot area of the bottom side.

33. A dance shoe, comprising: a distal part having a rigid toe box for encasing at least a portion of a forefoot of an intended wearer and supporting a foot of the intended wear; an intermediate part coupled to the distal part and configured for receiving at least a portion of a midfoot of the intended wearer; Atty. Docket No.: BCH2039PCT 34 a proximal part coupled to the intermediate part and configured for receiving at least a rearfoot portion of the intended wearer; a sole unit comprising a sole shank extending longitudinally from the distal part to the proximal part; and an interlocking component configured to interconnect the sole unit to the rigid toe box.

34. The dance shoe of claim 33, wherein the rigid toe box comprises a material having a first rigidity and wherein the sole unit comprises a material having a second rigidity.

35. The dance shoe of claim 34, wherein the material having the first rigidity is a different material from the material having the second rigidity.

36. The dance shoe of claim 33, wherein the interlocking component comprises a protruding or insertable locking component protruding from one of a bottom surface of the sole unit and a bottom surface of the rigid toe box, and an aperture in the other of the bottom surface of the sole unit and the bottom surface of the rigid toe box, the aperture configured to receive the protruding or insertable element.

37. The dance shoe of claim 36, wherein the interlocking component comprises a plurality of protruding locking components and a plurality of apertures.

38. The dance shoe of claim 33, wherein the interlocking component is configured to removably interconnect the sole unit to the rigid toe box.

39. The dance shoe of claim 33, further comprising a plurality of hinges, each with a unidirectional stop being disposed widthwise in the sole shank in at least the forefoot portion so that a forefoot portion of the sole shank locks by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of the foot and follow dorsiflexion of an intended wearer’s forefoot, wherein a portion of the sole shank in a midfoot position permits plantar flexion of an arch of the intended wearer’s foot.

40. The dance shoe of claim 33, wherein the rigid toe box comprises a first plurality of hinges disposed on an outer surface of a bottom side of the rigid toe box, each hinge with a unidirectional stop being disposed widthwise across the bottom side so that the bottom side locks Atty. Docket No.: BCH2039PCT 35 by the unidirectional stops to support plantar flexion and hinges to facilitate dorsiflexion of an intended wearer’s forefoot.

41. The dance shoe of claim 36 wherein there is an aperture in the toe box bottom surface that is centrally disposed between lateral and medial portions of the bottom surface, the aperture being disposed over a majority of the length of a forefoot area of the bottom surface, the aperture and the protruding or insertable element having complementary shapes that engage and couple to one another. Atty. Docket No.: BCH2039PCT 36