Escher + mathematics = ???

THANK YOU http://www.lookmind.com/illusions.php?cat=1&id=1886
M C Escher the artist.

Escher was passionate about drawing what infinity might look like.

What mathematical language can we use to describe his drawings?

What does infinity mean?

THANK YOU http://lynnandhorst.blogspot.co.nz/2011/07/miusing-escher.html