10 (More) Baffling Optical Illusions

If you enjoy the first one, as follows are 10 more awesome optical illusions:

1. Hermann Grid Illusion

   
   
   Discovered in 1870 by Ludimar Hermann while reading a book, this illusion is characterized by grayish shadowlike spots being perceived at the intersections of light-colored grid on a dark background. These shadowlike spots tend to disappear when one stares directly at the intersection.

2. Hering Illusion

   
   
   Discovered in 1861 by the German physiologist Ewald Hering, Both vertical lines of the image are straight but they look as if they were curved outward. The bend is caused by the background lined patterns, which somehow created an impression of depth.

3. Motion Illusion

   
   
   A type of optical illusion, in which a stationary image seems to be in motion caused by the intermingling of contrasting color shades and the arrangements of the shapes.

4. Orbison Illusion

   
   
   First discovered in 1939 by the psychologist William Orbison. Due to the presence of the diverging/converging lines that somehow give us an impression of depth, the consequence is that one is misled to see both the bordering rectangle and square inside it as distorted.

5. Isometric Illusion

   
   
   Also called an inside/outside illusion, this type of illusion is subject to two valid interpretation, or what is known as multistable perception. In the above illustration, the shape can be read as either an inside or an outside corner.

6. Kanizsa Triangle

   
   
   First reported in 1955 by the Italian psychologist Gaetano Kanizsa, this illusion misleads one to perceive a white equilateral triangle where none was actually drawn. In addition, the imaginary triangle seemingly looks whiter than the adjacent area, but it is in reality of the same intensity as the background.

7. Checker Shadow Illusion

   
   
   
   The left image shows what seems to be a black and white checkerboard with a green cylinder placed on one corner casting its shadow across to the opposite corner. The black and white squares are in fact made up of two dissimilar gray colors. However, the illusion has been deliberately created with the “white” squares in the shadow (one of which is marked B) as having exactly of the same shade as the “black” squares outside the shadow (one of which is marked A). Though squares A and B appear different on account of the illusion, they are the same as the image of the right illustrate.

8. Sander Parallelogram

   
   
   Documented in 1926 by the German psychologist Friedrich Sander, the blue diagonal line of the left parallelogram may look significantly longer than the red diagonal line of the right parallelogram, but in fact they are of the same length.

9. Poggendorff Illusion

      
   
   First documented in 1860 by the German scientist Johann Poggendorff, this illusion involves interplay between the diagonal lines and horizontal and vertical edges. In the illustration, the left image displays a straight black and red line partially covered by a gray rectangle. Instead of the red line, the blue line is wrongly ascertained to be the connected to the black line, which is certainly not the case as the right image shows.

10. White Illusion

    
    
    This illusion involves relative brightness perception. It is worth noting that the all the gray rectangles are of similar luminance, however, the ones which are seen in the context with the dark stripes are perceived to emerge brighter than the ones with the bright stripes.