Robert Rauschenberg, Retroactive II 1963. "Rauschenberg’s early experiments at Black Mountain College, a hotbed for innovation in the late 1940s and early 1950s where he embarked on his first collaborations with fellow artists and friends John Cage, Merce Cunningham, Jasper Johns, David Tudor, Cy Twombly and Susan Weil."
A space plan for Merce Cunningham’s Summerspace, 1958. The drawing contains the idea for the whole piece: six dancers, six entrances, each dancer will make all 21 possilbe crossings of the space using 21 different kinds of movement phrasing. The order of events was derived from chance operations.