Pendulum Wave
Cabinet of Arithmetic · Case 37Fifteen pendulums, each a little shorter than the last. Let go together, they fall out of step, and in one minute, to the instant, fall back in.
Fig. 1the row, seen from the front
Fig. 2the same row, seen from above
towards the wall
towards you
rate
pendulums
space pause ←→ step a second touch a bob to single it out