Standing at ten and a half feet high, Five Rudders is composed of a large tripod base painted bright red that balances a sequence of black sheet-metal elements at its apex. A signature work by the American sculptor Alexander Calder, Five Rudders is a hybrid form known as a standing mobile, or a stabile-mobile. It incorporates both a stabile—an abstract construction that is completely stationary—and a mobile—a sculptural work in which motion is a defining property. Calder’s sculpture functions like a weathervane: the vertically oriented black “rudders” can be placed in motion by a strong gust of wind.