The hoberman mini rainbow sphere is an expanding and contracting ball it cleverly combines mathematics and geometry to create a surprising motion that fascinates children and adults alike why not give these tricks a try flip down hold the closed sphere by one hub on top of your open palm flip the sphere over and watch it open then flip it back to the top of your palm and let it close when yoursquove mastered this try it with your other hand open bounce hold the sphere fully open with two hand