A rhythm is a return. Something happens, time passes, it happens again, and the distance between the two events is the whole of it. The sequencer I learned on drew a rhythm as a strip. That drawing is true about order, but it says nothing about coming back. When the playhead reached the right edge and leapt to the left, that leap was the most important thing in the music and the least visible thing on the screen.

I started with a small question: could the line just be wrapped into a circle? The leap disappears, because a circle has no edge to leap from. The return stops being the thing you can't see and becomes the shape itself. And a shape can be read the way a line can't. The distance between two hits is an arc now. Patterns I would have called different turn out to be the same shape, rotated a few steps. On a ring there is no first beat, only the one you start on.

But a loop is rarely one element. A beat is a kick, a snare, a hat: three or four of them turning at once, each on its own ring. They just turn together. So I stacked them. They line up exactly, and the one you see is the one you are playing. The others are directly underneath, and all it takes to see them is a different angle.

A drawing can make the case, but an instrument has to be played. So I built Rings as an iPhone app, so that anyone could pick it up and try the idea with their own hands. That raised a second problem. Everything the instrument can do is a gesture on the rings, and there is nothing on the screen to explain a gesture. So the app teaches itself. It opens on two ways in, Play and Learn, and Learn walks through each move in turn, waiting for you to make the move before it goes on.