Note: please visit Eyetricks 3D if you would like a custom stereogram created featuring your own message or logo.
An stereogram is a is a picture within a picture. The creators have cleverly hidden a 3D object inside an unusual looking 2D picture. But the brain can only create the illusion of depth when you learn how to view the stereogram correctly.
For information on how to see the effect, please visit the Wikipedia article on Autostereograms.