-motion aftereffect
Java applet: counter-rotating spirals illusion
http://dogfeathers.com/java/spirals.html
-optical illusions
Visual phenomena, optical illusion, visual illusion
http://www.michaelbach.de/ot/index.html
-optische illusies
Optical illusions ilusiones ópticas optische täuschungen illusion d'optique optical illusion gezichtsbedrog optische illusie ilusões de óptica optyczne iluzje
http://www.optillusions.com/
-optische illusies (2)
Amazing optical illusions! - optical illusions, optic tricks, magic and brain teasers. includes old and new illusions, illusions that you can view on your pc and some you can do at home yourself (diy illusions).
http://www.opticalillusions.ws/