Fooling Your Senses:

Distortions

Are the long, black lines parallel?

The figure at the right gives your brain a lot of information. Sometimes, too much information can start to overwhelm your sense of what you are seeing. The long black lines are indeed parallel. (So are the long, orange lines.) The small "fins" branching off of the long lines tend to pull our eyes in certain directions, causing us to see angles that aren't really there.

Are these vertical lines parallel?

The many angled lines again pull your eyes away from following the vertical lines. Therefore, many people see the vertical lines as "bulging" near the middle. This type of illusion is called a "Distortion" because the image looks warped from what it really is.

Similar illusions:

Are these horizontal
lines parallel?

Are the white circles the same size?

How about the black circles?

(You can use a ruler to check any of these.)

The Cafe Wall Illusion:

The famous illusion at the right comes from having the tiles improperly aligned on a tile wall. The horizontal lines begin to look slanted. Builders and artists have to be careful to avoid unwanted optical illusions in their work.

For an interactive version of this illusion, click here.

The Stovepipe Hat:

A tall "stovepipe" hat, like Pres. Lincoln is famous for wearing, is almost exactly as wide as it is tall. Don't believe it, measure for yourself!

The same illusion can be seen in the geometric figure at the right.

Parallelogram distortion:

In the parallelogram, the diagonals are the same length. But our brain likes to compare the areas of the two smaller parallelograms for extra, false information.

Spiral Illusions:

In the following diagrams, our brain insists that the image is a spiral. However, if you look closely, no spiral exists in any of these.

Bulging Tiles:

An even more powerful illusion is found here. In this image, every tile really is the same size, and all lines are parallel. (Measure it if you don't believe.) The pattern of smaller squares makes your eyes insist that the tiles are largest in the middle.

Impossible puzzle:

In this final illusion, check out the change made to the large triangle when the pieces are rearranged. Each colored piece is the same in the top and bottom diagram. (Use the grid or measure if you want to check.)

Why, when the pieces are rearranged, is there a missing square? The only clue for the answer is that this page is all about distortions: Not everything is what it looks like.