Hi, its Ann E. Student again.
I have just found the museum of perception 
and cognition in Belgium, with some VERY
interesting demonstrations by Marielle Lange! 
After you get there, click the button on the left 
for Illusions.  Try the Mueller-Lyer illusion.
It is really neat! 
To visit a section in English, click on the link 
below:




Graphic used by permission of Marielle Lange of the Museum of Perception and Cognition, Université Libre de Bruxelles, Belgium