Optical Illusions

Can you believe your eyes? (1)

Can you believe your eyes?

Well, can you?

Which looks bigger?

Which red circle is bigger?
The Lipps Illusion ~ 1897

Parallel or curved?

Are the red lines curved?

Square and circle?

Is that a square and a circle?


Are you certain you can see a spiral?

Colour Spiral or Concentric Circles

What about this one ? A spiral or concentric circles ? Sure ?

spots before the eyes?

Are you seeing spots before the eyes yet? - The Hermann Grid
The intersection you look at won't change colour, but the others will !!

Moving dots

A variation of the Hermann Grid

Moving dots

How many black dots are there?
A variation of the Hermann Grid

engulfing darkness

What happens when you stare at the center of this image?


What about the stripes in the circles? Sure?


What is going on here?
Thiery's figure

Zollner Illusion

The Zollner Illusion - The longer lines really are parallel!

Triangle 1 triangle 2

How many triangles can you see in each of these 4 pictures
1, 2 or none?

If you see an upside-down triangle in these pictures, what happens to its shape in the bottom right picture?

triangle 3 triangle 4

Kanizsa figures

This page created June 3, 1999; last modified July 24, 2021