US Patent 7338056 One piece flexible skateboard

A flexible skateboard may include a pair of direction casters mounted for steering rotation a twistable one piece skateboard. A center section may be made sufficiently narrower than outboard foot support areas which may be twisted by a rider to add energy for rolling motion to wheels in the casters. The center section may also be made sufficiently resistant to twist so that the skateboard may be ridden as a conventional, non-flexible skateboard.