Murmur
watch simple rules turn into music
watch simple rules turn into music
Murmur runs an elementary cellular automaton (Wolfram's rules 0 to 255) and plays it as it evolves. One row of cells is computed each beat and drawn top to bottom like a piano roll. The moment a row is calculated, every live cell in it triggers a note, so the pattern scrolling down the screen and the melody in your ears are the same event. Nothing is pre-recorded and there are no audio files: each note is a Web Audio oscillator shaped by a short envelope.
The rule itself is the instrument. A rule is an 8-bit number, and Murmur lays those 8 bits out as 8 switches, one for each three-cell neighbourhood. Flip a single switch and the next row changes shape and the notes it plays change with it, immediately, with no restart. Notes are quantised to a scale you pick (major, minor, or pentatonic) and a root note, which is the trick that keeps even chaotic rules like rule 30 sounding musical instead of harsh. Set the tempo from 1 to 12 steps per second, mute with one button, and reset to draw a fresh random pattern.
Every pattern you land on lives in the URL. Rule, seed, scale, root, and tempo are all encoded in the link, so the Share button copies a URL that reproduces the exact same picture and the exact same sequence of notes for anyone who opens it. Found a rule that sounds good? Send the link. There is no account, no install, and nothing to configure before the first sound plays.
If you want somewhere to start, the preset gallery collects rules that are known to be interesting: rule 90 draws the Sierpinski triangle, rule 110 is Turing-complete, rule 184 models traffic flow, and rule 30 is genuinely chaotic. Pick one and it starts playing straight away.