Please visit their site.  This is 

 only a small sample of their 

  wonderful collection of illusions 

The four illusions below
come from


on 11/26/2005


. .
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.


Hidden Rope Trick

Which rope is continuous
from top to bottom?

Use the slider tool
(click or drag slider button)
to make the vertical bar
dissolve away. Were you correct?

If the ropes were aligned
perpendicular it would
be easy to pick the right
answer. We are very good
at linear tracking, but
when the rope is steeply
inclined, it is much
harder to follow the correct
path of either rope.

Flash Movie: ©2003 Tony Azevedo


 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!


Flash: ©2002 Tony Azevedo..............

White's Illusion 

The rectangle on the left
is mostly surrounded by
white. The rectangle
on the right is mostly
surrounded by black. Which rectangle appears lighter?
Use the slider bar
to move the rectangles
back and forth. As the
rectangles overlap
you see that they
are identical. Colors
appear lighter when
they are surrounded
by white, and darker
when they are surrounded
by black. This is a color comparison problem using
two identical rectangles
against a b&w background. 


That's all sixty-six illusions.  Please send me new ones to add to the collection.