'I am interested in perceptible processes' Reich had written in 1968. 'I want to be able to hear the processes happening throughout the sounding music.' Four Organs is a radical realisation of this goal. Against the steady rattle of maracas, individual tones within a single chord are gradually lengthened. No changes of pitch or timbre occur, and the drawn out nature of the process provoked outrage at some early performances, when audiences found themselves caught up in a decelerating loop, being dragged towards stasis. Phase Patterns, composed a month later, relies on a phasing technique developed during Reich’s earlier experiments with magnetic tape recordings, which he allowed to drift out of sync. Identical figures initially in unison shift out of phase, generating unexpected patterns.