How is this possable?

[Kryton]

Been looking at this for ages but i cannot see how this picture is possable.

 

[sneaker]

You have to love an impossible picture

 

[nara]

If you like having your brain messed with you should explore the works of M.C. Escher.

Sneaker's post above is one of his works.

 

[avid]

A clever deception using different in drawing angles.