AP lab

http://www.rpbusa.org/rpb/eye_info/how/

http://bcs.worthpublishers.com/myers7e/

http://www.exploratorium.edu/explore/online.html

http://kids.niehs.nih.gov/illusion/illusions.htm

http://www.vision3d.com

http://www.subliminalmessages.com/plane_charter_9.htm