This guy is apparently very well known in Europe and parts of the U.S. I have no idea how he makes money at something like this, given how temporary it all is. But some of the stuff that he does is pretty extrodinary. These are only a few samples. The top picture in the series illustrates how he must "stretch" his drawing to make it look as if it pops out of the sidewalk when viewed from the correct perspective. All in all, quite an unusual (to say the least) talent to have cultivated.