| Dated: | 1958 (A) and 1959 (B) |
| Instrumentation: | A: String ensemble (3, 0, 0, 3, 3) B: Two / Four-channel tape |
| Timing: | 7' |
| Premiere: | Summer 1959 at the Gravesano Festival, performed by the Festival Orchestra, dir. Hermann Scherchen |
| Dedicated to: | |
| Commissioned by: | Service de Recherche of the ORTF (Analogique A) |
| Published: | Editions Salabert 17169 |
| Both works should be performed simultaneously. The tape was created at GRM (Groupe de Recherches
Musicales) in Paris, France. Recording available at Vandenburg 3. |