Hmmm the image on the wall makes me think of Ray Johnson ("How to Draw a Bunny") or Keith Haring, but since neither of them are alive you can't be expecting visits from either of them, so either it's someone else or I'm WAY off base or totally missing something obvious. Meanwhile, since the guy working on the wall has a beard, I doubt he's on of your elementary students... I hope you'll let us know for those of us who don't "get" it from this post!
I have no idea?! Tell:)