"Rocks" is composed of two carved Styrofoam sculptures suspended from the ceiling, set six feet apart from each other. Each sculpture contains a custom-wired functional speaker system within, and when combined, serve to function as a complete stereo system.
Sonically each rock has its own droning vocal track, with the voice of one priest in on rock and the voice of the other priest in the opposite rock. Secondly, each rock is playing a phase inverted combination of sine waves with frequencies calculated to collide most effectively in the space between the rocks.
Since phased inverted sine waves cancel out each other when they collide, the space between the rocks is in effect one of the "quietest" parts of the room to stand in.