Your shape sits on a map where every triangle is a chord, and neighbouring triangles share two notes. Each corner plays the chord it lands in. Notes the two chords share are held, only the rest move.
Turn on more than one to layer them. Each new layer is pushed an octave lower or higher, and you can change it.
Depth adds a short, soft reflection around each note. Fade out keeps the first half of every loop at full volume, then lets it get quieter towards the end.