This rocks, so I’m writing this as a service to you, who also rock. Developed as an artsy-fartsy design thing by Jean-Louis Fréchin & Uros Petrevski, FabLabWall is an iPhone app that basically works in the spirit of those decoder rings your grandparents found in cereal boxes as kids. You know those scannable bar codes popping up on billboards these days, yeah? Basically, FabLabWall is the same sort of thing, but works in real time: just aim your iPhone at wallpaper designed for use with the app, and hidden embedded text and images are revealed, augmented-reality style. It does not get cooler…