Mobile - stable
Terms coined to describe innovative sculpture created by Alexander Calder. Mobiles are hanging, movable sculpture, and Stabiles rest on the ground and may have some moving parts but are generally immobile. In the 1920s, Calder began experimenting with constructions that involved motion, and by 1932, he had his first wind-driven Mobiles. Usually the Mobiles are hung from ceilings, but some of Calder's are suspended in the air from a base. From the late 1930s, Calder was creating Stabiles, which are characteristically abstract black metal sheets bolted or welded together. By the 1960s, he was doing many of these for outdoor settings, and some were large enough that people could walk through them. Source: "Phaidon Dictionary of Twentieth-Century Art"