According to musicologist Keith Potter, "Piano Phase" led to several breakthroughs that would mark Reich's future compositions. The first is the discovery of using simple but flexible harmonic material, which produces remarkable musical results when phasing occurs. The use of 12-note or 12-division patterns in "Piano Phase" proved to be successful, and Reich would re-use it in "Clapping Music" and "Music for 18 Musicians". Another novelty is the appearance of rhythmic ambiguity during phasing of a basic pattern. The rhythmic perception during phasing can vary considerably, from being very simple (in-phase), to complex and intricate.