http://sorabji.com/p/picture_essays/Stuff_People_Write_on...
Even though it’s a violation of Title 18 of the U.S. Code, we all do it — write on U.S. currency, that is. Here’s a site that gives a glimpse into the weird stuff people draw on dollar bills, ya’ll. Frankly, I’m surprised there’s not more porn-inspired doodles.