In 1973 in his New York City loft, Brazilian artist Hélio Oiticica and his collaborator Neville D’Almeida pioneered an immersive form of participatory installation they dubbed Block-Experiments in Cosmococa—Program in Progress, or Cosmococas, for short. These multi-sensory “quasi-cinemas,” with their heady mix of projected images, soundtracks, and props, effectively recast the passive film viewer as active participant. In this essay, art historian Irene Small locates CC5 Hendrixwar amidst various historical threads of avant-garde film, semiotic theory, loft performance, and radical pedagogy.