How to Laser Tag (i.e. graffiti) a Building

John3 writes: "The Graffiti Research Lab has posted video of laser graffiti they created on a Rotterdam building. The effect is very cool, and a complete guide on how they did it is posted on Theodore Watson's website. All you need is a laptop, LCD projector, and laser and you too can graffiti buildings without any permanent damage (unless you fry the retinas of a curious late night janitor). The GRL site states they are "dedicated to outfitting graffiti artists with open source technologies for urban communication" and there are several other examples of previous high-tech graffiti experiments, including drive-in GIF theater."