This so called false optical illusion is created by overlapping segments that appear to form a spiral; however, the arcs are really a series of ordinary circles.
The Ebbinghaus illusion
This optical illusion of relative size perception is named after German psychologist Hermann Ebbinghaus. This illusion consists in misperceiving the size of circles. In this version, as shown in the picture, two circles of identical size are placed close to each other. One is surrounded by large circles while the other is surrounded by small ones. The central circle on the right then appears bigger than the left central circle.
Impossible Cube illusion
This impossible cube was invented by Charles Cochran in 1966. The illusion of depth in this picture occurs because of incorrect connections between the cube’s corners. Do not even attempt to unravel the secret of this unrealistic figure.
In the Zöllner optical illusion, the parallel lines, crossed with a numerous oblique short lines, appear to diverge. This effect was accidentally discovered on a cloth pattern by German astrophysicist Johann Zöllner in 1860.
This illusion was first demonstrated by Joseph Jastrow, an American psychologist. It lies in the fact that two figures that are absolutely identical appear to be different in size when they are arranged in a certain way.
This triangle illusion is named after the Italian psychologist Gaetano Kanizsa. To prove that people experience reality not as it really is but as it is seen through special filters called mental models, he drew a series of geometrical figures giving an impression that there is a bright white triangle in the center. However, this triangle doesn’t really exist at all.
It’s a classic optical illusion named after Johann Poggendorff, a German physicist. A scientist discovered it in the picture received from F. Zöllner, a famous astronomer. This illusion shows that in the example above, the black line on the left appears to be a continuation of the blue line. In actuality, the black and red lines match up. Interestingly, this optical effect hasn’t been explained so far.
Blivet, also known as impossible trident, is a classic example of geometrical-optical illusions. No matter how hard you try, you have no chance to understand this figure — it simply doesn’t exist.
At first glance, this illusion seems contrary to common sense; the gray rectangles are exactly the same color but they appear different because of the contrasting neighboring colors — white and black.
Certain color contrasts and shapes of the patterns depicted in the picture make you think that a static image is moving.
Hermann grid illusion
Ludimar Hermann discovered this optical effect in 1870 while reading a book on sound by John Tyndall. In the Hermann grid illusion, the "ghostlike" gray spots appear at the intersections of white (or light colored) lines on a black background. These spots disappear when one looks directly at an intersection.
An elderly couple, or songs to a guitar accompaniment
Just look at this loving elderly couple. And now take a closer look. What do you see this time?
Illusory rotating effect
Focus your eyes on a black dot in the center, then, move your head slightly forward and backward. If you look at the picture again, you will see the outer circles rotating in the opposite directions.
The illusion of "The Wall Cafe"
Carefully look into the picture. At first glance it seems that all the lines are curved, but in reality, they are parallel. This optical effect was discovered by Richard Gregory in the Wall cafe in Bristol, where it got its name.
Rotating wheels illusion
Take a look at the picture. You are likely to see the wheels spinning in different directions. But if you focus on any wheel individually, it will stop turning, but the wheels around it will.