The author examines some ideas behind three computer works (Fusione Fugace, Electric Etudes, Spectres Parisiens) that he composed at IRCAM. Fuzione Fugace (1982) is for three performers (keyboards) and a live computer. Electric Etudes (1983) was composed for cello and live electronics. Spectres Parisiens (1984) was composed for three solo instruments, chamber orchestra, and computer tape.