Adapting Mutation Step Size to an ANN Topology

A play and exercising device comprising a hoop and a ball disposed substantially at the center of the hoop and connected to the hoop by at least four tensioned, radially disposed elastic strings or lines. In use, the ball is held in a hand and, through motion of the hand, the ball is oscillated back and forth thus causing the hoop to also oscillate back and forth relative to the ball, the amplitude of oscillation of the hoop being a function of the force applied to the ball and of the resiliency of the radial elastic strings or lines.