The ARP 2500 is legendary vintage monophonic analog modular synthesiser equipped with a set of sliding matrix switches above each module to interconnect them with one another. It is the first product of ARP Instruments Inc.; several such synthesisers have been built from 1970 to 1981 (the year the artist has been born). Even if the 2500 has been proved to be a reliable and user-friendly machine, it failed commercially – selling just about 100 units. Its successor, the ARP 2600, comprises a collection of the its most popular modules yet leaving out the matrix switching and the more esoteric functions of the 2500.

The artist committed to creatively explore Worm’s ARP 2500 over a period of several days. Rather than experimenting with unorthodox strategies (as the he largely did with the Buchla or with the Serge) he resorted on the very fundamentals of sound synthesis: carefully thought-of configurations, long rudimentary forms, organic rhythmical patterns, minimal user-interaction.