To fully emulate the human leg will involve motors, the mechanical equivalent of muscles, and electrical sensors that gather the same input as the human nervous system.

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The 57-pound device is a robot that a human could wear over his or her body either to assist or inhibit movement in leg joints.

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Made from every manner of material--from ivory and brass to animal teeth and mother-of-pearl--tampers come in a wonderful variety of motifs, including a horse's hind leg, a bust of Oliver Cromwell, a milkmaid and, yes, a human finger.

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