Black Frame is a celebrated example from a series of motorized “frames” and “panels”—or three-dimensional paintings—that Calder developed in Paris in 1931 and continued to explore in Roxbury in the mid-1930s. He described the motorized mobile in a September 1935 letter to collector A. E. Gallatin: “One I like very much myself is a black wooden frame, with sheets of metal within it, warped into various planes, and having certain moving elements, which are brilliant spots in an otherwise somber se