Includes a new image every week demonstrating stereograms.

Contains many optical illusions, illustrating a wide range of visual anomalies and surprising optical effects. A free screensaver, posters, and educational explanations are also provided.

Illusions organized by category, including blind spot, blink effect, bordering, chromatic adaptation, colorblindness, and others.

Java applet, including other illusions, such as an animated Necker cube.

Interactive illusions, including Benham's disk and other illusions involving motion.

Interactive animations and optical illusions that respond to user's input.

Interactive optical illusions, games, science projects, fun puzzles, and distortions.

From the Department of Opthamology and Visual Science at the University of Illinois, a collection of illusions and after images.

Interactive illusions from the exploratorium.

Some classic optical illusions with explanations for how they work.