How cool is this?
A very progressive type of art, not surprisingly coming straight from Germany: LichtFaktor, a group of artists that became famous for their light grafittis.
I love the concept, very innovative. Finally a solution to keep the good things of graffiti without being out the law and troublesome, nor buying paint. Besides, the 3D aspect and light effect just makes it a lot nicer than even the best paint-on-wall grafitti.
More technically speaking, it seems that they use a camera with a shutter open for the time they need to move the lights around. I still wonder how they manage to delete whatever or whoever is holding the lights.