My favorite type of graffiti... Eric @ Wired writes -

A street artist has got to have a serious bone to pick to keep on working in front of shouting, gun-waving cops. Then again, I guess Alexandre Orion had a bit of an advantage when the police tried to nab him in a São Paulo street tunnel: He wasn't painting city property, he was cleaning it. For over two weeks last year, the Brazilian artist selectively scrubbed soot from the tunnel until the white surface underneath stared through as a cemetery's worth of skulls.