Synchronization

Thirty-two metronomes are started off in pretty much random beats. Over time, they sync up with each other, sort of like the positive feedback resonance people on a walking bridge experience, which has caused troubles in the past. See, the surface they sit on is suspended, so that each device's "bounce" affects the others. Watch the pink metronome on the right, second row from the front. It tries to maintain its individuality, but even he eventually bows to the pressure of the sympathetic vibration on the suspended surface and falls in line with the horde. (via The Daily What Geek)