Is it a ball? A star? A crazy experiment? The award-winning Hoberman Sphere is a little of everything. Created by Chuck Hoberman, it expands and contracts with a magical motion using a combination of geometry, engineering and art. Throw it. Bounce it. Kick it. It?s irresistibly interesting. Made of linked plastic studs. Magically expands from 9.5″ to 30″. Includes activity sheet. For ages 4 years and up.