Alexander Calder was most famous for his kinetic sculptures, or “mobiles,” but he also imbued his stationary “stabiles” (a term suggested by artist and friend Hans Arp) with a sense of movement and lightness. Alfred Barr, a graduate of the Princeton Class of 1922 and the first director of the Museum of Modern Art, approached his friend Calder to discuss designing a work for Princeton. Calder replied that he would find it “fun to make something especially for you, and quite big.” On Barr’s suggestion, the disks of the resulting work were painted orange to honor Princeton’s colors, in anticipation of the artist’s post-installation visit to Princeton in 1971. Surveying his sculpture with a shrewd eye, Calder walked through and around it, scanning it from various angles and from the top of the thirteen-story Fine Hall tower. He then gave quiet instructions to the painters, and the four orange disks were gradually blacked out, one by one. The form of the stabile is considered Calder’s most important contribution to twentieth-century art.