Sequencing & generative
A synth makes one sound; a sequencer decides when. Some even write the part for you.
Everything so far has been about making a single sound. Sequencing is the other half of a synthesizer: deciding when the notes happen. A sequencer is a little machine that plays a pattern in perfect time, forever — and some can even invent the pattern themselves.
The classic sequencer is a step grid: a row of slots, and you switch on the ones you want to fire. But the pattern above is made a cleverer way. A euclidean rhythm spreads a number of pulses as evenly as possible across a number of steps — and it turns out that this one simple rule produces the traditional rhythms of half the world. Try 5 pulses over 8 steps, or 5 over 13, and listen.
Generative music
Push the idea further and the machine stops repeating and starts composing. Feed a grid to the rules of Conway's Game of Life and the pattern evolves every bar; roll dice inside a scale and you get an endless, always-in-key melody. That is generative music — you set up a system, and it plays itself.