There are many different kinds of optical illusion, and the mechanisms behind them are different from each other. Most are reasonably well understood, some are still in question. See links for ideas.
Here is a personal speculation: Those things around us that we can see clearly, with little or no ambiguity, are probably those things that were important to our survival during our evolution.
No, it is not an optical illusion.
yap.. its just an optical illusion
All mirages are optical illusions but all optical illusions are not mirages.
OpTiCaL ILlUsIoN WaZ MaDe fOr ArT AnD FoR tHe InJoyMeNt oF thE PeOpLE
Optical illusion challenges will increase sharpness of your brain. Also the increasing visual literacy is also possible through optical illusion challenges.
It is in your question already. An illusion will never be real. If it was real then it would be no illusion. Optical illusions are in a way real. They are real optical illusions. We can however not fake an illusion because the illusion is fake from start.
Bored Panda is a great website which offers a number of different optical illusion pictures. You can also find optical illusion pictures from Yahoo! Images.
NO
The fog created an optical illusion.
The Müller-Lyer illusion is an optical illusion consisting of a stylized arrow.
its an optical illusion
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