the visual system constructs surfaces when portions of the surface's edge are not visible. The encoding of surfaces is thought to be an indispensable part of visual perception, forming a critical intermediate stage of visual processing between the initial analysis of visual features and the ability to recognize complex stimuli like faces and scenes. Amodal perception Autostereogram Filling-in Gestalt psychology Negative space Phantom contour Reification References Further reading External links Illusory contours figures Many unpublished drawings (fr) Optical illusions Triangles