Three suede-covered foam pieces that work as one course: a 37-in square ball pit, a 29-in triangle climber and a 20-in step block. Push them together and a child takes the steps, crosses the triangle and drops into the pit; pull them apart and each piece stands alone. High-density sponge gives the walls enough firmness to lean on without folding over. Concealed zippers keep pull tabs away from small fingers and every cover unzips for machine washing. Balls are not part of this package. The 21-lb set arrives ready to use with nothing to assemble.