condition (record/cover): NM / EX- (minimal ring wear)

Laurie Spiegel composed the four pieces here between 1974 and 1976 at Bell Telephone Laboratories in Murray Hill, New Jersey, using the GROOVE system (Generating Realtime Operations On Voltage-controlled Equipment) developed by Max Mathews and F.R. Moore. GROOVE was a hybrid digital-analogue setup: a 3C DDP-224 computer in one room, voltage-controlled synthesizer modules in another, the two connected by long runs of cable. Spiegel wrote her own real-time interaction code in FORTRAN IV and 24-bit DAP assembly.

No major classical label would touch the record. Spiegel placed it instead with Philo, the Vermont folk label run by Bill Schubart: an unexpected home for what is now recognised as a foundational document of American algorithmic composition. The title track was, at the time of pressing, among the longest single sides ever cut to vinyl; the loud-soft dynamic range pushed the lacquer-cutting limits. Spiegel's Harmonices Mundi, her computer realisation of Kepler's planetary harmony, was included on NASA's Voyager Golden Record the same year. The 2012 Unseen Worlds 2CD reissue added fifteen tracks from the same Bell Labs period.