1. Fraser's Spiral
Otherwise known as the 'false optical illusion' this image is made from several overlapping circles that appear to be in spiraling motion. However, the image is actually made up of normal circles. It's what is going on inside the circles that causes you to perceive eternal motion.
2. Ebbinghaus's Illusion
It's amazing how we assess the size of something relative to what surrounds it. This illustration from German psychologist Hermann Ebbinghaus demonstrates this effect simply and clearly. Have a look at the orange circles and consider how big they appear relative to one another. They are actually the same size, yet because one is surrounded by large circles it appears small, whereas the one surrounded by small circles appears big.
3. An Illogical Cube Illusion
Charles Cochran conceived this impossible cube in 1996, yet I am still unsure how. Can you work out how the corners of this cube actually come together? As a 2D image it makes sense, but when your brain imagines it as a 3D cube, the haywire begins.
4. Zollner's Illusion
Another image that creates the illusion of depth was accidentally noticed on a piece of cloth by Johann Zollner, a German astrophysicist, in 1860. Because some short lines go from top to bottom, they appear to be standing up at an angle, whereas the short lines that go left to right appear to be lying down on an imaginary surface.
5. Jastrow's Illusion
Is there anyone who doesn't feel that these shapes are of a different size? In fact, Joseph Jarrow's A and B illusion shows two identical images placed in a certain position. For some reason, our minds cannot visualize that they are the same.