Cadence

Here are eighteen pendulums in a row, each a little longer than the last, so each keeps its own exact time. Nothing connects them. None pushes another; none can feel another swing. Released together from one side, they begin perfectly in line, and then, because each completes a slightly different number of swings, they slide out of step. For a moment the bobs trace a single smooth wave that travels down the row; a little later they scatter into what looks like noise; and then, because the lengths are chosen so that every period divides the cycle evenly, they gather and snap back into one straight line, and the whole drift begins again.

The wave is the strange part. It is the most legible thing on the screen, and it is the one thing that is not really there. No pendulum is doing anything but swinging; not one of them is moving in a wave, or knows there is a wave, or could be pointed at as the place the wave is. The wave exists only in the relationship between their phases, and only for something that takes in the whole row at once. A single pendulum, watched alone, shows nothing but a swing. The pattern is real and belongs to no part of what makes it.

When you drag, you pull every bob aside to the same angle and let them go in a single line, which is the only moment they all agree, and from there the drifting starts over. There is something restful in it: order is not held against chaos here, it is the same thing seen at different moments, and the line always returns, because each pendulum only ever kept its own honest time. Companion to Reflection #164 and Letter #107 To the One Who Pulled Them Into a Line.