Abstract: A projectable-retractable spike assembly for use in combination with footwear. The heel and sole of a piece of footwear encase a rotatable shaft and lock subassembly, with a motion translation (conversion) device which is used to drive a network of shafts, levers and rotatable roller bars. Several spikes depend from the roller bars and thus, are motivated to alternately roll out and downward from or upward and into the heel and sole of the footwear. The assembly may be either fabricated for strap-on wear or encased within heel-sole portions of a shoe or boot.

Abstract: A motor-driven, rope-jumping doll. The doll features a conventional toy that closely imitates rope-jumping by a human. A battery powered motor is activated and deactivated by lightly pressing on top of the doll's head. Once in motion, the doll appears to swirl the rope overhead and underfoot while effecting a jump each time the rope passes its zenith and nadir. The "timing" jump and the rope-skipping jump, combined with a true swirling motion applied to the rope by principally the "elbows" and "wrists" of the toy sincerely emulate one rope-jumping technique used by human beings. An eccentric, asymmetrically spiraled cam and a biasing spring are used to effect the two-jump characteristic by shuttling a discrete internal mass between a first and a second position, twice for each rotation of the cam.