Cage's pioneering use of electronic musical resources began in 1939, with his now-classic percussion ensemble composition Imaginary Landscape # 1, in which he employed variable-speed phonograph turntables as performed musical instruments. Cage's artistic innovation with electronic technology continued into the 1940s (e.g., with music for a CBS Radio Drama production of Kenneth Patchen's City with a Slouch Hat). Early electronic-music and magnetic tape In the Cunningham repertory the first notable work to use electronic music resources was Collage (1952), choreographed to excerpts from the Symphonie pour un hom me seul by Pierre Schaeffer and Pierre Henry. This landmark of "musique concrete" was composed using sounds recorded and edited on disk; in the Cunningham Dance Company performances the music was played using a tape recording.