Optical illusions are a delight. Puzzles for the eye, they play with our expectations, our deductive abilities, our biological blindspots, and our ability to process light, shadow, motion, and perspective.

We’ve featured optical illusions several times before, from the large-scale works of Felice Varini to the mystery of the Necker Cube, but we never seem to run out of clever ways to deceive the eye and conjure magical effects from the simplest materials.

So today, I thought we could indulge ourselves in some first-class visual trickery. =)

Our first video was produced by Samsung, and features 10 optical illusions in 2 minutes. Can you suss out the techniques being employed?

This next illusion is a prime example of after-images (the most famous one being the American flag with black stars, a tan/yellow field, and black and blue/green stripes).

Forced perspective (like that in the LEGO picture at the top of the page) has been a cherished film and photographic trick for decades — from Darby O’Gill and the Little People to Honey I Blew Up the Kid — and here’s a particularly wonderful illustration of how effective forced perspective can be.

Finally, we have the video that inspired this entry, courtesy of the science-minded folks at IO9.

There is a famous mathematical conundrum known as the triangle paradox (or Curry’s triangle paradox, after magician Paul Curry), wherein it appears that you can lose or gain area from a shape by cutting it into pieces and moving them around.

The video illustrates the concept behind the triangle paradox by offering an intriguing promise: how to cheat mathematics and make chocolate out of nothing. (Warning: watching this video may aggravate your sweet tooth.)

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