Optical illusions- monocular distance cue of depth

Anybody that has surfed the internet has no doubt come across optical illusions. A classic optical illusion is that most people have come across is the Mueller-Lyre illusion.

The Mueller-Lyre illusion makes the line segment (a) appear long than the line segment (b). This illusion is cause by something called the monocular distance cue of depth. The edge in line segment (a) looks similar to an edge that is normally further away from us.

Another illusion based on the same principle is the Ponzo illusion. Both yellow lines are of the same length yet the one higher up in the image appears to be longer.

It is optical illusions such as these that remind us what we see does not always accurately reflect the world but is what our minds interpret the world as. 

What are you favorite optical illusions? I am always interested in new optical illusions. I leave you guys with another great optical illusion, the Checker Shadow illusion. I would put money on squares being the same color. That's how much the illusion gets me. :)

(Reproduced from wikipedia). This illusion is a type of contrast and depth illusion.

For more optical illusions, check out the wikipedia page.