Thanks guys :)
This was, of course, based on the concept of Steve Reich's "Piano Phase", where two pianos play the same music, but one slowly and gradually speeds up, causing a delay effect that gets longer and longer as the piece plays.
I only used the concept, not any of the musical ideas, and my piece uses three pianos instead of two.
Also recommended is Reich's "Four Organs" which is the same concept applied to four electric organs over an 8th note maraca pattern.