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M.C. Escher

From the website:

Maurits Cornelis Escher (1898-1972) is one of the world's most famous graphic artists.
His art is enjoyed by millions of people all over the world, as can be seen on the many
web sites on the internet.

Everything you've ever wanted to know about M.C. Escher:

http://www.mcescher.com/.
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