Figuring Out These Puzzling Optical Illusions Is Almost Impossible

An elephant with too many legs; a shark hidden among random colored dots; a checkered café wall that distorts parallel lines. These are just some of the extraordinary optical illusions that we’ve unearthed for this piece. Keep your eyes open and hold onto your brain for an amazing journey through a weird world of distortion and visual trickery.

20. Magic Eye

Stare at this enigmatic image for a while and you’ll get a surprise if you focus on it in just the right way. Not everyone can see the likeness of a multicolored shark hidden among the seemingly random pattern of dots. It’s all a question of throwing your focus off to reveal the fish, which emerges in three-dimensional glory. Magic Eye books caused a sensation in the 1990s, dividing people into those who could see the concealed objects and those who couldn’t.

How does it work?

Although this image shows you the shape of the shark, it is a pale imitation of what it’s possible to see in the full picture. The magic works because of the fact that humans have two eyes. Each sees a slightly different view, but the brain knits the image together. A Magic Eye picture exploits this difference with its arrangement of dots. If you focus through the picture you’ll see the concealed object within it. 

19. The Café Wall illusion

It was a British psychologist called Richard Gregory who first named the Café Wall phenomenon. Why did he settle on the name? Well, it was because he had literally spotted the illusion in the brickwork of a café in the English city of Bristol. Look at the lines running across the picture. They’re not parallel are they? Oh yes they are — prove it to yourself with a ruler. 

How does it work?

It’s the pattern of the bricks that makes the lines appear to be off-kilter. And here’s the late Professor Gregory outside the café where he spotted the illusion. Precisely how it works is not fully understood. The Illusions Index website says that “it appears to involve interactions between the neurons in the visual cortex which code for orientation.” Hope that clears things up.