The goal is to display piano notes without using musical notation. Notes are shown on top of piano keys. To replay them, the library MIDI.js and with it e.g. WebAudio is used. The image shows the progress of compactifying the display, where first only needed keyboard keys are drawn, and second repetitions are not redrawn.
Recognize the music? Solution: ⅁N∩HƆS∩Ǝ∀⊥ 'ƎSIƎᴚᴚƎ⊥NIM ⊥ᴚƎ𐐒∩HƆS