Here’s an innovation I hope becomes standard in every city in the world. Walls in the neighbourhood of Hamburg, Germany have been coated with a hydrophobic layer, meaning that when late night revelers attempt to use the streets as their urinal, the urine will not only be repelled off the wall, but it will also splash back onto the user. It helps protect the cleanliness of the city, while giving the perpetrator a light reprimand, and reminder to use the bathroom. The walls are hung with the sign warning that these walls “pee back”. If this campaign is run effectively, perhaps just a sign will be enough to deter the action!