If the images above aren't quite impressive you might need a little context to understand just what you're looking at. Middle school science teacher Michael Wallace, 39, of Baltimore, Maryland has been creating these pictures, etch-a-sketch style, onto his GPS-enabled phone for the past couple of years. The end result is something that looks like what a 3 year old would do with a crayon, but considering the medium he's working with is considerably more impressive. As he explains it, the project began with an attempt to scrawl his name, "Wally," onto a map of the US via a GPS-tracked bike ride. He's gone on to create some fairly intricate work, compiled at his site Wally GPX for your viewing pleasure.