I can't think of how to describe this, other than graffiti with light (Macromedia Director required). While the site itself doesn't contain much information on how it was done, it contains some amazing images of graffiti etched into empty space.

It looks as if they have used a multiple camera setup (as made famous in The Matrix) with long exposures to capture images of people and light from multiple angles. This is the sort of concept art I can appreciate.