Yesterday I was looking some logical games to download, and I found one intersting(spelling?) site with mental testing stuff and great visual illusions. .
Here are my favorite samples (illusions)
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This amazing illusion is called dancing elephant. Try to count the number of his legs.
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There is nothing moving on the picture. (© Akiyoshi Kitaoka)
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When you first look at this, how many colours do you see? Some might say they see 3 or even 4 colours, but there are 2 - red and green! People usually think they see 2 shades of red, but there is only 1. Look closely and you will notice on one side that white boxes surround the red boxes, and on the other side, green boxes do! Due to the placement of these boxes you get the "illusion" of different colours. Since white is not considered to be a colour (it is the presence of all colours in scientific terms) we can safely say that there are 2 colours present here! Still don't understand?
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For more visit
http://hlavolamy.szm.sk/brainteasers