Crossview

A crossview stereogram. It can be viewed by crossing your eyes until the images line up. Here is a link to a zoomable cross-eyed stereo viewer application: XVRWiki's crossview viewer

Crossview, also called cross-eyed stereo, is a method of viewing a 3D image using a flat 2D display or print. It involves crossing one's eyes to overlap two images to form 3D perception.

A crossview image has a left part and a right part. In a crossview image, the eyes are crossed. The left eye is looking at the right portion of the image, and the right eye is looking at the left.