The toilet walls at work had been used for Graffiti for years, most of it not for family viewing.
In an attempt to stop the "artists" the walls were painted black and a white board put up, this did the trick for some time but now this. In the cubicle next to this the black paint has been peeled from the wall, unfortunately its adhesive power was so great that the wall is now back to the plaster as it took all previous layers of paint with it. http://www.pbase.com/image/49922886