Sync is the mathematics of how independent systems can synchronize their state. (Hacker News discussion) When multiple metronomes are placed on the same table they sync up their ticking over time, but if more metronomes are placed on the table they don’t necessarily sync up. The additional metronomes can form their own sync clusters. I think sync can serve as a more general theory of music, explain why there are different types of particles in the universe, and explain high temperature superconductors (and perhaps lead to room temperature superconductors). Perhaps there is some connection to emergence theory.