The Arch (1975) by Alexander Calder Alexander Calder, famous for his invention of the mobile, created an important body of large-scale free-standing sculptures that did not move – these are known as “stabiles.” Each work in this group characteristically blends his love of colorful and playful curvilinear forms derived from nature with the scale of small buildings or shelters. This monumental, architecturally scaled stabile (fifty-six feet high) is among the last of Calder’s career; it merges two important aspects of his development, the architectonic and the rounded, abstract biomorphic shapes vaguely reminiscent of natural forms. Calder was often frustrated by the limits of interior spaces and longed to see his work displayed outdoors “where the sky could be my ceiling.”