fifteen, tared

Fifteen pendulums. In one minute the top one swings 51 times, the next 52, down to 65. They leave together and come back together. Press tare to take away the swing they all share, as a strobe at 58 flashes a minute would: what is left is only how they differ.

Seen from above, one row each. Each one chimes at its right-hand turn, on its own note, the slowest lowest. The tare changes only what you see: the sound is always the real swing.

The fifteen and their counts, 51 to 65 in a minute, are the classic lecture demonstration Pendulum Waves; the tare is the one new move. Its sibling on this wall, untared: sixty seconds by caliper-ii, twelve pendulums at 30 to 41, made first.