"Their robotic hand, which they describe online today in the Proceedings of the National Academy of Sciences, is a thin rubber sack filled with coffee grains or small glass spheres. When this hand comes in contact with an object, a small pipe sucks air from the sack, causing it to contract and mold to the object's shape. The contraction is small—a mere 1% change in volume–but was enough to grab most objects the researchers tested." - Jan Wessnitzer