Tau, by American sculptor Tony Smith, was designed in the early 1960s. It is 14’ high x 12’ wide x 12’ deep, and made from black painted steel. Its title refers to the Greek letter 'T', which also describes the shape of the sculpture. Fascinated by mathematics, biology and crystals, Smith designed Tau with geometry at its root. There are two extant versions of the large sculpture: Tau (AP), and Tau (1/3).