If a Graffiti Printer Writes With Sand Is It Still Really Vandalism?

Gijs van Bon's Skryf machine is far from the world's first automatic graffiti machine. But it could be the first that won't have law enforcement ready to throw the cuffs on him. That's because the self-propelled device uses a modified CNC milling machine to 'print' messages on the ground using nothing but harmless… » 1/30/14 6:00pm 1/30/14 6:00pm