Word illusions.

Illusions come in many different ways, as you all know they may vary from 3D to 2D. Illusions have the power to make your brain work by filling in the blanks. A good example of this:

In case you are wondering is says: No sex causes bad eyes

Another prime example of words and illusions would be this 

An idea inspired from ancient times, the most famous would be the Illuminati wording on the now popular novel by Dan Brown.The idea of making a word look the same any way you see it was a big deal. Leonardo Da Vinci was one of the few people to think of the idea and try doing it.
Mirror writing is also a type of skill/illusion, this image shows it pretty well. Plus the girl is nice :)

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