autostereogram

thumb|300px|A random dot autostereogram encoding a 3D scene of a shark, which can be seen with proper viewing technique. (10px)

275px|thumb|The top and bottom images produce a dent or projection depending on whether viewed with cross- or wall- eyed vergence. thumb|Autostereogram of a cube rotating, to be viewed with cross-eyed vergence. thumb|Autostereogram An autostereogram is a two-dimensional (2D) image that can create the optical illusion of a three-dimensional (3D) scene. Autostereograms use only one image to accomplish the effect while normal stereograms require two. The 3D scene in an autostereogram is often unrecognizable until it is viewed properly, unlike typical stereograms. Viewing any kind of stereogram properly may cause the viewer to experience vergence–accommodation conflict.