There’s an audio illusion that’s somewhat analogous to the barber pole illusion — instead of a pattern which appears to always go up or down, you can have a sound which seems to always go up or down in pitch: https://en.m.wikipedia.org/wiki/Shepard_tone
There’s an audio illusion that’s somewhat analogous to the barber pole illusion — instead of a pattern which appears to always go up or down, you can have a sound which seems to always go up or down in pitch: https://en.m.wikipedia.org/wiki/Shepard_tone