By 1931 Calder had begun to make nonrepresentational sculptures, in many cases experimenting with counter balance and air currents to set his works in motion. Applying the dynamics of his Circus to these abstract constructions, Calder used different forms and densities to create ever-changing spatial configurations. For Object with Red Discs, one of the earliest of his wind-driven sculptures, Calder cut simple shapes out of sheet metal, attached them to wires, and used wooden spheres to offset their weight. Although many of these early “mobiles,” as they were called, balanced on bases, Calder began to suspend them from the ceiling in 1932.
