64=65?

I'm pretty new here so i don't know wheter this is going in the right place but i was surfin da web when i found this:
www.planetdan.net...
after watching this animation numerous times, and actually drawing a grid and copying it with cut out shapes and measuring with a ruler it still seems that 64 does equal 65, waht i want to know if this is actually the case.

can anyone tell me why this works, or why it looks as if it works?

Pretty cool, but alas is just an optical illusion. The shapes don't fit together perfectly.

This link explains all:

neurobashing.com...

omg, thank you, its been doin mine and my friends heads in for ages

thanks Observer