A few geometric illusions to trick your brain

Here are some geometric illusions from an excellent (free) online database. The database is the Visual Perception Library, http://viperlib.york.ac.uk which was co-created by a great guy I used to Juggle with in York.

Enjoy! :-)

(and as I haven't contacted you yet - thanks Rob, very cool work).

In the Zollner illusion, these long lines are really parallel


Do the blue lines twist up and down like a water flow? This illusion is mainly due to lateral inhibition. (Apparent motion.)


The image appears to be moving before your eyes due to the fact your lens is not perfectly round so not all of the image can be seen sharp. The result of this is that the eye constantly makes small movements