1. Zöllner Illusion

In this figure the black lines seem to be unparallel, but in reality they are parallel. The shorter lines are on an angle to the longer lines. This angle helps to create the impression that one end of the longer lines is nearer to us than the other end. This is very similar to the way the Wundt illusion appears. It may be that the Zöllner illusion is caused by this impression of depth.

2. Blivet


A blivet, also known as a poiuyt, is an undecipherable figure, an optical illusion and an impossible object. It appears to have three cylindrical prongs at one end which then mysteriously transform into two rectangular prongs at the other end.

3. 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.

4. Hering Illusion


The Hering illusion is an optical illusion discovered by the German physiologist Ewald Hering in 1861. The two vertical lines are both straight, but they look as if they were bowed outwards. The distortion is produced by the lined pattern on the background, that simulates a perspective design, and creates a false impression of depth.

5. Jastrow Illusion


The Jastrow illusion is an optical illusion discovered by the American psychologist Joseph Jastrow in 1889. In this illustration, the two figures are identical, although the lower one appears to be larger.

6. Bezold Effect


The Bezold Effect is an optical illusion, named after a German professor of meteorology, Wilhelm von Bezold (1837-1907), who discovered that a color may appear different depending on its relation to adjacent colors. In the above example, the red seems lighter combined with the white, and darker combined with the black.

7. Fraser Spiral Illusion


The illusion is also known as the false spiral, or by its original name, the twisted cord illusion. The overlapping black arc segments appear to form a spiral; however, the arcs are a series of concentric circles.

8. Adelson’s Checker Shadow Illusion


The image shows what appears to be a black and white checker-board with a green cylinder resting on it that casts a shadow diagonally across the middle of the board. The black and white squares are actually different shades of gray. The image has been constructed so that “white” squares in the shadow, one of which is labeled “B,” are actually the exact same gray value as “black” squares outside the shadow, one of which is labeled “A.” The two squares A and B appear very different as a result of the illusion.
9. 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”.

10. 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.

Interesting, isn’t it?

Source: Wikipedia