The descriptions of stereograms and Magic Eye pictures as being a single image, but with one copy slightly offset from the other caught my attention. It says the 3D image you get from even random data is the result or artifact of our own visual processing. This is precisely how so-called "binaural beats," work, where instead of images, they are slightly offset tones, one played in each ear, and the mind gets clipping and feedback effects by trying to reconcile the otherwise inaudible differences in the offset tones.