Rhys Chatham had his musical education in the world of ‘60s New York minimalism, then later found his own direction by mixing this with the raw energy of the downtown No Wave sound. In terms of scale his work has covered the extremes, from a piece for 400 massed electric guitars to solo explorations; it is the latter he will be performing at Fort Process, a piece involving phased trumpet and guitar loops called Pythagorean Dream, named after the guitar tuning it employs.