1) Optical illusion 2) Sirds
Found on
https://www.crosswordclues.com/clue/autostereogram
An autostereogram is a single-image stereogram (SIS), designed to create the visual illusion of a three-dimensional (3D) scene from a two-dimensional image. In order to perceive 3D shapes in these autostereograms, one must overcome the normally automatic coordination between accommodation (focus) and convergence (angle of one`s eyes). The illusio....
Found on
http://en.wikipedia.org/wiki/Autostereogram
No exact match found.
