Come In/Go Away

I love stuff like this symbiotigram doormat. Besides being cool and useful art, it could take the place of the "towel on the doorknob" in places like dormitories and shared multiple-bedroom apartments -- as long as you're not in such a hurry that you forget to give the thing a flip...

John Langdon is an artist who specializes in this kind of graphic art. Among other projects, he did the cover art for Dan Brown's Angels and Demons. Check out his entire website for some truly amazing and imaginative designs. Then try to see if you can visualize your own name done as an ambigram.