What: This illusion should hit fairly clearly, there is a checker board pattern, with a small diagonal set of checkers within each corner with an alternating pattern. This pattern though, switching the black and white squares starts to twist your mind, and suddenly it seems like the lines, especially around the edges are on angles rather than perfectly vertical.

This particular effect, I first ran into in a blog called Revolution Analytics[1], whereby the owner was creating effects using the programming language R. My own version is a JavaScript extension of the same effect, with a few twists (such as the animation, and the ability to stop it at any time.)

How To: Just stare right at this bad boy, and try to pretend you’re steering straigh through perfectly parallel lines. You can also click anywhere to stop the animation and see the effect without the movement. After watching in animating for a while, the stopped effect feels extra strange.

Explain it: There are a few optical illusions on this site that are using a similar trick, one being the spirals [2], and another being the straight line squares [3], both of these illusions, at least according to my research use a combination of either offset or angled squares. When your brain tries to process this information it starts to make assumptions about repeating patterns, or patterns based on what often appears in nature, albeit in this case, it is incorrect.

Cites and Extras:

• 1 Revolution Analytics, This optical illusion coded in R, including the code, and a few other great illusions.
• 2 Spiral Effect, an illusion that makes it seem as though the concentric circles are spiralling via angles.
• 3 Straight Line Squares, an optical illusion that again fools your brain using angles.

I've researched these optical illusions in my spare time but am clearly not any kind of expert and my explainations are pretty smooth brained, if you find something mis-cited, earlier examples, or general mistakes please new let me know via toymaker@toms.toys, be kind!