Mobile

Alexander Calder, Eagle, 1971, painted steel, Olympic Sculpture Park, Seattle, WA
Alexander Calder's Balancing Act in Art and Life
Iconic American sculptor Alexander Calder (1898―1976) invented “mobiles”―carefully balanced, often whimsical kinetic hanging sculptures, powered by wind or motors.
Alexander Calder metal mobile sculpture
The Calder Mobiles that Asked to be Touched
A custom sign planted in MoMA's sculpture garden in 1943 said "Please Touch," signaling to visitors at Alexander Calder's retrospective that it was okay to handle the kinetic sculptures and mobiles.