Impossible figures in advertising
A set of advertising images with impossible figures for Pirelli was created by Francisco Arranz.
Besides it, a huge image of impossible triangle was painted on a wall as anamorphics image. Some parts of the triangle are painted on different walls of the building, and all parts of the image put together from a single point of view.
Images were found at http://www.behance.net/gallery/Pirelli-The-reason-behind-madness/2145131.