Whadda concept. Reverse graffiti uses grimy urban surfaces as canvasses—creating art by washing images and words onto soot-covered tunnels and filthy walls.
Authorities are not quite sure what to make of this—can you arrest someone for cleaning the city? When Brazilian artist Alexandre Orion created a mural of skulls in a Sao Paolo tunnel to remind drivers of the environmental impact of car emissions, authorities responded by cleaning the wall. Orion then clean-graffitied the other side. And according to inhabit.com, the authorities responded by cleaning every tunnel in Sao Paolo.
Reverse graffiti. What do you think?