Alexander Calder is celebrated for developing the mobile as an art form. He combined his interests in nature, abstraction, and motion to create sculptures that perform.
Alexander "Sandy" Calder (; July 22, 1898 – November 11, 1976) was an American sculptor known both for his innovative mobiles (kinetic sculptures powered by motors or air currents) that embrace chance in their aesthetic, his static "stabiles", and his monumental public sculptures. Calder preferred not to analyze his work, saying, "Theories may be all very well for the artist himself, but they shouldn't be broadcast to other people."