Calder attributed his creation of kinetic sculpture, especially the mobile, to a 1930 visit to Piet Mondrian's studio in Paris, where he was drawn to boards that Mondrian had painted red, blue, yellow, black and white and had tacked on a pristine white wall. Calder remembered seeing these panels and imagining how they might move.
Untitled probably dates to the mid-1940s. Its date is suggested by its careful arrangement of forms, a more sophisticated design than that found in earlier mobiles. Initially, Calder worked primarily with wooden spheres and painted wire, usually favoring an open tripod base for his standing mobiles. By the forties, he preferred a planar tripod base, using painted wire only as the connector between the mobile elements and the base. In subject and inspiration, many of Calder's mobiles reflect his fascination with developments in astronomy. In the Phillips work, the yellow form perhaps refers to the sun while the flat discs attached to the elegantly curving, twisting wire may allude to planets, each on a different axis and rotation, with their movements suggesting their orbits.