Bells ring overhead, prompted by the pull of a handle. Plastic rings with polka dots circle bent bars of galvanized steel. A volleyball seesaws along a metal channel from one basket to another. Guiding these movements with wonder and wide grins are children usually excluded from playground activities, children whose physical and mental disabilities prevent them from swinging or sliding with their peers. The forlorn expression on a wheelchair-bound boy's face as he watched his carefree siblings jump, run, and giggle inspired Richard Neiman to found Basic Skills, Inc., a Fort Lauderdale company that produces playground equipment for disabled children. The newly incorporated business unveiled its educational designs in December at Anniversary Park, possibly the only playground to provide comparable pleasure for children of all abilities. The bright colors and innovative shape of "The Basketball" may seem striking now, but Neiman hopes that eventually it will be as commonplace as the sandbox by its side -- the children straining to tilt its baskets not so different from those constructing castles out of sand.