Campaign for Vancouver's Sculpture Biennale where three-dimensional posters for the festival, were spread throughout the city. With a tagline like "Art that you can feel,"
The 3D posters also featured empty pedestals - the kind you use to display sculptures -- so that passersby could leave something of their own (personal or found) on them. This, in essence, made people the artists, and what they left on top of the pedestals became their art. The wall becomes an interactive public gallery.
Via: AdArena/Invisible Red