monkeyzoo writes: San Francisco is testing an ultra-water-repellant paint on 10 walls in areas fraught with public urination problems. The paint is designed to repel the urine and soil the pisser's pants. "It's supposed to, when people urinate, bounce back and hit them on the pants and get them wet. Hopefully that will discourage them. We will put a sign to give them a heads up," said Mohammad Nuru, director of the San Francisco public works. A Florida company named Ultra-Tech produces the super-hydrophobic oleophobic nano-coating that was also recently used with success on walls in Hamburg, Germany to discourage public urination [video]. Signs posted there warn, "Do not pee here! We pee back!"