Trio A, choreographed in 1966, became the first part of Rainer's best known performance, The Mind Is a Muscle (1966–68). The artist herself is the dancer in this film documentation from 1978. Rainer's emphasis on ordinary motions and gesture is readily apparent, and the dance is an exploration of action rather than a vehicle for dramatic storytelling. Rainer cofounded the Judson Dance Theater in 1962, and together with her colleagues she questioned the role of dance as a modern art form.