Interlock 5 has been written for 5 or 6 performers controlling a single sawtooth wave generator. The performers control the frequency of the same monophonic sound throughout the entire piece. However, they don’t control the frequency simultaneously, but are competing for control.
Only one of the performers can set a new pitch at a time. Since the performers play a polyphonic musical text, it is impossible to determine in advance who will actually be in control at any given moment.
The musical text of the piece is a simple version of Philip Hayes’ (1738 - 1797) round “By the waters of Babylon”, which was introduced to a wider pop music audience in a simplified version by Don McLean in the early 1970s. Some years later Gerd Kern wrote German Lyrics to the tune, whereupon it became popular in Germany in the 1980s, originally as a protest song against nuclear armament.

Nach dieser Erde wäre da keine, die eines Menschen Wohnung wär’.
Darum Menschen achtet und trachtet, dass sie so bleibt!
Wem denn wäre sie ein Denkmal, wenn sie still die Sonn’ umtreibt?

Roughly translated:

After this earth there would be none that could be a human's home.
Therefore people watch it, protect it, so it remains!
Who would bother if it floated quietly around the sun?