1. Hermann Grid Illusion
The Hermann grid illusion is an optical illusion reported by Ludimar Hermann in 1870 while, incidentally, reading John Tyndall’s Sound.
The illusion is characterised by “ghostlike” grey blobs perceived at the intersections of a white (or light-colored) grid on a black background. The grey blobs disappear when looking directly at an intersection.
2. Ebbinghaus Illusion
The Ebbinghaus illusion is an optical illusion of relative size perception. In the best-known version of the illusion, two circles of identical size are placed near to each other and one is surrounded by large circles while the other is surrounded by small circles; the first central circle then appears smaller than the second central circle.3. The Chubb Illusion
The Chubb illusion is an optical illusion wherein the apparent contrast of an object varies dramatically, depending on the context of the presentation. Low-contrast texture surrounded by a uniform field appears to have higher contrast than when it is surrounded by high-contrast texture. This was observed and documented by Chubb and colleagues in 1989.
4. Café Wall Illusion
The café wall illusion is an optical illusion, first described by Doctor Richard Gregory. He observed this curious effect in the tiles of the wall of a café at the bottom of St Michael’s Hill, Bristol. This optical illusion makes the parallel straight horizontal lines appear to be bent. To construct the illusion, alternating light and dark “bricks” are laid in staggered rows. It is essential for the illusion that each “brick” is surrounded by a layer of “mortar” (the grey in the image). This should ideally be of a color in between the dark and light color of the “bricks”.
5. Motion Illusion
One type of motion illusion is a type of optical illusion in which a static image appears to be moving due to the cognitive effects of interacting color contrasts and shape position.
To properly view this effect, click the image above to see the full sized version.
