Every Friday, I visit my friend at his studio. I show up, we chat for a few minutes, then spend an hour clapping together. We’re learning Steve Reich’s 1972 composition “Clapping Music.” The piece consists of one simple rhythmic phrase clapped repeatedly by two performers over the course of 13 sections. It begins with both players — named “clap 1” and “clap 2” in the score — beating the phrase in sync. Clap 1 loops the same pattern throughout the piece, while clap 2 shifts and inverts the phrase for each section. You can imagine it like two analog stopwatches set off at the same time, gradually going out of phase with one another; they remain *in time* but are passing through the minute cycles at different moments, creating dense syncopated effects.