Reminded by Mr. Knauss that I have one too, this is my equivalent of a woodshopped sign.
It’s a “flat stanley” made by a senior homeroom for a competition they have. (Each homeroom makes a different flat stanley and takes it around New York City taking pictures of it in various locations.)
Continuous Everywhere but Differentiable Nowhere 
Dang, I’m jealous! I want a flat Stanley too.
I ***LOVE*** this! When my niece was little, she sent me a Flat Stanley and as I recall from the photographic evidence, he took a lot of naps with the dog. ;-)
Elizabeth (aka @cheesemonkeysf on Twitter)
I’m putting together a list of the top 100 high school/secondary school teacher blogs and your site was recommended by another blogger on the list. I was wondering if I could ask you a few questions via e-mail so I can include more information in my article. Please e-mail me at alexisbrett@gmail.com and include the title of your blog in the e-mail, thanks!