That's not R5-D4's brother, it's a modded Wiimote that a German student envisions for use in a virtual graffiti world.

Martin Lihs, student at Bauhas-University in Weimar, built the "Wiispray" for his thesis. He wants the wall to encourage graffiti artists to express themselves without the artistic encumberances of balancing on a highway overpass railings, getting chased by railroad police, or, like getting arrested.

Sounds fun and creative but people tag up real walls for a reason -- real people see 'em. All the commissioned murals, coffee table books and contests for graffiti artists provide real recognition to, but not like getting up on a warehouse wall. The essential act of graffiti is painting where you're not supposed to paint, right?

WiiSpray Prototype Graffiti Controller for Wii [Slashgear, via Engadget]