Phosphor Draw
A true vector oscilloscope. The glowing shape you see and the tone you hear are the same stereo signal — X is the left channel, Y is the right. Geometry becomes timbre; the loop’s replay rate becomes pitch.
Audio needs a tap to begin. Then a figure-8 will draw itself and sing.
Or draw your own closed loop on the scope with finger or mouse — a circle hums clean, a star buzzes bright, a square is rich with harmonics.