Disappearing Flux-Music for Envelopes

Published by Fluxus Edition, New York
Nine envelopes, one of them with a cardboard attached on
the surface bearing the writing "Shadow pieces"
Large envelope: 11.6 x 17.3 cm.

Part of "Fluxus Envelope Paper Events" No. 0016S and
"Fluxyearbox 1": book version, No. FX1250