Multi-layered Sock This invention relates to a sock with a multi-layered structure, the primary purpose being for the treatment and prevention of plantar fasciitis in the human foot. 5 Background of Invention Plantar fascia is the thick connective tissue which supports the arch on the bottom of the foot. It often becomes painfully inflamed from overuse by eg. running, heavy 10 weight bearing and long periods of standing. Treatment is long term and involves a combination of rest, massage, physiotherapy, stretching, splints, hot/cold packs, steroids and in limited cases surgery. The more intensive the treatment, the less painful and quicker the recovery period will be. Pathologies of this structure and neighbouring pedal anatomies can be difficult to treat and recalcitrant. 15 Splints previously used for treating plantar fasciitis such as US 2002/0188239 TURTZO, EP 1778139 OUTRED, are cumbersome and not readily adaptable to daily life, nor can they be used with everyday shoes. 20 Summary of Invention The object of this invention is to provide a sock composed of multiple layers useful for the treatment and prevention of plantar fasciitis. 25 According to a first aspect a multi-layered sock comprising: a) an outer layer; b) an inner layer shaped to cover the sole of the foot and/or up the side of the foot to the desired height, and is attached to said outer layer along said inner layers' shaped 30 edge ; c) a plurality of middle layers, each having the same shape as said inner layer, are attached to said outer layer and/or said inner layer along said inner layer's shaped edge, such that all said layers are free to move against each other between said attached edges; 35 d) each alternating layer of the above said layers of said multi-layered sock being composed of a different material. In accordance with a further embodiment, said inner layer and said middle layers are 40 cut to shape so as not to visible whilst wearing a shoe. In accordance a further embodiment, the multi-layered sock is made of both natural and polymer fibres. 45 In accordance with a further embodiment, the sock is made of natural fibres comprising one or more of cotton, wool, viscose, bamboo or similar materials. In accordance with a further embodiment, the sock is made of polymer materials such as elastane, nylon, lycra or similar materials. 50 1 In accordance with a further embodiment, the inner layer and plurality middle layers extends to a height below the ankle. In accordance with a further embodiment, the layers are attached by one or more 5 methods comprising knitting, sewing or gluing. In accordance with a further embodiment, the attachment occurs at either one level or at staggered levels. 10 In accordance with a further embodiment, said multi-layered sock is a stocking. Brief Description of Drawings 15 In order that the present invention may be fully understood and readily put into practical effect, there shall now be described by way of non-limitative example only preferred embodiments of the present invention, the description being with reference to the accompanying illustrative figures, which are not to scale. 20 Fig. 1 is a side view showing an example of the multi-layered sock of the present invention as applied to a human foot. Fig 2 is a front cross-sectional view of an example of the present invention as applied to a human foot. Fig 3 is a side view showing an example of the multi-layer stocking of the present 25 invention as applied to a human foot. Fig 4 is a side view showing an example of the multi-layer stocking of the present invention as applied to a human foot in the flat position. Detailed Description of the Invention 30 Fig 1 shows an innermost layer 3 in contact with skin of a human foot 4. A second inner layer 2 covers the innermost layer 3. Inner layer 2 is of the same dimension as innermost layer 3. Both of these layers end at the approximate area above the ankle 5. Outer layer 1 covers inner layer 1 and extends past inner layer 2, past the ankle and up 35 the leg to a normal exercise length sock height or of sufficient length to ensure the multi-layer sock remains in place whilst the sock is being worn by the person. The number of layers can be increased to 4 or 5 or more. The limit would be determined by the practicality of fitting into an everyday shoe. It is envisaged that the height of the sock could extend to the knee or beyond, according to the desired treatment or 40 condition. In another embodiment, the plurality of inner layers may extend only to a height below the ankle to avoid overheating in hot weather. Figs 1 and 4 show the frictional forces (ie shear forces) (small arrows) in the primarily longitudinal direction between the multiple layers and the horizontal pull on the 45 Plantar fascia (large arrow), all in the direction of the heel to toe and toe to heel. The rubbing and sliding of the multiple layers of different composition of the sock against each other causes a reduction in the pulling of the plantar fascia which is the cause of the pain of plantar fasciitis. 2 The attachment of the inner layers and the outer layer may be by knitting, occurring either during manufacturing or sewing after manufacture. The attachment may also be by gluing or any other means considered appropriate. The attachment may occur at one level or at staggered levels as shown at dotted lines in Fig 1 so as to avoid a large 5 seam. Optionally, layers may also be attached in the toe area or around circumference of the sole. This still allows the required movement of the layers against each other to generate the shear forces to dissipate the horizontal pull on the Plantar fascia. Another embodiment of the present invention, as shown in Fig 3, allowing the use of 10 the sock as a "knee-hi" or trouser sock or stocking, would involve the outer layer 1 extending to just below the knee with an elastic band around its circumference, as currently used in the art, and the plurality of inner layers 2,3... n, would be positioned as described above but attached just below the ankle bone 5, where n is the maximum number of layers. The inner layers would also be scooped in shape around the top of 15 the foot and stitched along its top edge so as not to be visible over the edge of the shoe. This would permit the wearing of court shoes 6 by ladies while still allowing treatment/prevention and some pain relief from plantar fasciitis without being obviously in a therapeutic boot. 20 The material used for the construction of the sock may comprise any suitable man made or natural fiber or blends thereof. Such materials may comprise polymer materials eg elastane, nylon, lycra, or natural fibers eg. cotton, wool, viscose, bamboo, etc. All of these materials are ready available and currently used in garment manufacture. 25 Some examples of the layering options could be: 1) Cotton blend - nylon blend - cotton blend 2) Cotton blend - nylon blend - nylon blend - cotton blend 3) Cotton blend - nylon blend - cotton blend - nylon blend - cotton blend 30 Whilst there has been described in the foregoing description preferred embodiments of the present invention, it will be understood by those skilled in the technology that many variations or modifications in details of design or construction may be made without departing from the present invention. 35 3