If you've ever lived in a bar neighborhood, you know the smell. It's the stench of idiots peeing all over the walls, doors, and sidewalks of your street—and until now, there really hasn't been a solution.
The proactive residents the "party district" of Hamburg took matters into their own hands by painting the walls of the neighborhood with hydrophobic paint, which repels water chemically— the same stuff we've tested here at Gizmodo on everything from t-shirts to toiletpaper.
When water (or pee) strikes the bricks or concrete at velocity, the coating repels it right back from whence it came. Or, in most cases, onto the shoes and paints of the offending urinator. They call it the "peeback."
There are all kinds of urban design tricks like this to stop all kinds of behaviors in cities, including paint that repels spray-paint, but this is a new one. Now, if only we there was a dog poop-proof paint for our sidewalks.