Audio Illusion

An audio illusion for once.

Play this video a few times - until the pitch of the sound becomes inaudible.



This is a neat example of a Shepard Tone - the illusion of a tone that continually ascends or descends in pitch without ever changing.

http://en.wikipedia.org/wiki/Shepard_tone

The impression of progress - where none in fact exists - is a common problem in IT projects...