Legal graffiti

I see this graffiti on a wall everyday on my way to work. The other day, I got tired of waiting for the bus, so I started walking, and eventually I came to this wall! Since there was still no sign of the bus, I decided to study the wall. I thought these characters were particularily interesting.

Next Day Note: Seems I hit some interference when I sent this picture. Those look like pictures of people, or am I just seeing things? Did I capture some All Hallows spririts? Certainly seems like it, as I can only post pictures on this blog sent directly from my phone's camera.