These non-repeating sounds come from a small electromechanical object that I built from 27 relays, 27 capacitors, and a bunch of wire scraps.

Listen for the rhythmic (and almost musical) phrases that slip in and out of phase as the machinery clicks along. In theory, it all should repeat after 14×13=182 cycles but, because of quasi-random irregularities in the jiggling mechanical elements, it never quite does.