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Please visit their site.  This is..

  a wonderful collection of illusions.

The illusions below
come from

SandLot Science.com

on 11/26/2005


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Spinning Chevrons

This design will generate
apparent motion even
though it isn't moving at all.

The motion is anticlockwise.
Keep your eyes moving
when you look at the image.
Use your peripheral vision
to see the illusory motion.


Dimples or Pimples?

The notion that light comes from above is persistent. We see it so often that it is hard to shake the notion. The dots in the grid on the left appear to be dimpled into the surface because the tops are in shadow, and the bottoms are bright, as if the light were shinning from above, right on them. The dots look like shallow craters.

Click on the image to flip the dots upside-down in groups of 16 in each quarter of the grid. Flip all the dots so that their dark rims are on the bottom. Where does the light appear to come from now?

Instead of logically assuming the light now comes from below, and that the dots are still dimples, we cannot help but assume that the light must still be coming from above. That the dimples are now pimples!

Source: http://www.sandlotscience.com/Guided_Tours/Tour2/Tour2_2.htm