• shepard tones
• Illusions
• audio
• Shepard Tone

Warning: may cause headaches, nausea, abject terror, uncontrollable laughing.

About shepard tones, in shepard tones.

Soundtrack is free here: https://soundcloud.com/vihartvihart/shepard-tones-soundtrack

This video is CC-by, feel free to re-use for any purpose with attribution.