The Hoberman Sphere is the original award winning geometric expanding/contracting ball. Made of linked plastic struts each one is a marvel of mechanical engineering. Pull on any of the sphere’s hubs and watch as it expands dramatically from 9.5” to 30”! Kids want to touch it, adults want to examine it, and everyone wants to play with it. All spheres come with a pulley, hardware and instructions to hang as a cool, kinetic mobile. An educational booklet about the geometry of the Sphere and a “21 Cool Things to Do” activity sheet is also included.