Halve it if even, triple and add one if odd, and every number ever tested falls to one — a conjecture Erdos said mathematics is not ready for, drawn as the tree of trajectories flowing back to the root; each hit launches a new seed and the hailstone path it takes is the music's.
Drawn with: a WebGL2 shader.
Reacts to and looks like: gpu, webgl2 and audio-reactive.
Family: Visualiser.
Runs in your browser. The preview above is the same program the renderer uses.