32 metronomes, all started at different times and synchronizing together.
Basically, the metronomes the table absorbs the vibration of the metronomes and starts having a rocking pattern of its own. The metronomes that are rocking with the table continue doing so, and the ones that aren’t begin to get weaker and then change their pattern to match the table.
It take like 2 minutes for all but one of them to match together. Cool stuff.