A Hoberman Sphere is a structure that resembles a geodesic dome, but is capable of folding down to a fraction of its normal size by the scissor-like action of its joints. They have become popular as a child's toy. Several sizes exist, with the original design capable of expanding from 15 cm (6 inches) in diameter to 76 cm (30 inches).
A Hoberman Sphere is not a true sphere, but a polyhedron known as an icosidodecahedron. The Hoberman Sphere can be unfolded by allowing certain members spread apart. This can be accomplished by feeding out a string or cable.
The largest existing Hoberman Sphere is in the atrium of Liberty Science Center in
Jersey City, New Jersey. Fully expanded, it is 5.5 m (18 feet) in diameter. It's motorized, weighs 318 kg (700 pounds), is made of stainless steel and aluminum, and is in continuous, automatic motion.
Its inventor, Chuck Hoberman, holds several patents on folding techniques many of which resemble the designs of Buckminster Fuller but for the folding aspect.
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