The Shepard Scale: An Amazing Auditory Illusion

Named after cognitive scientist Roger Shepard, a Shepard scale is an auditory illusion composed out of a series of ascending or descending Shepard tones. To start the Illusion, hit the play button, and be sure to replay the video again and again and again. I can assure you that you’ll be questioning your sanity after listening to it a few times.

[Via Neatorama]