Op de Fles ("On the Bottles") by Frans Geysen. For 4 players: 16 bottles (or 4 Recorders). Flanders Quartet Series. Score and parts. Duration 6 minutes. Published by Heinrichshofen Verlag (PE.N02597).
The would-be players must collect 16 beer and wine bottles, and fill them with liquid (unspecified) so that they produce the intended pitches. Each player must play four bottles, two at a time. A strong bottle embouchure is the most important prerequisite for performers. The piece uses only 16 pitches, but getting the right pitches to sound in the right rhythms on bottles is quite a demanding feat. Of course it may be played on four recorders, but I doubt that it would result in the same musical or visual effect as a bottle performance.--Anita Randolfi, for American Recorder (January 2009)
Four players and sixteen bottles (or four recorders). Score and parts. Flanders Quartet Series Volume 8.