Cool set! It looks almost like a typical clipart schoolhouse from the outside, if all clipart was designed by urban explorers (now there's a thought!). Those windows in numbers six and seven... you won't see any school these days with something as humane and thoughtful as natural light! Love the texture on number 5.
All that graffiti though-- I don't really get why people always see the need to draw dicks on things. Do the think they're insulting someone, or being transgressive, or do they just lack imagination? It's not transgressive, it's not insulting, it's just a bad drawing of genitalia. Get over yourselves!
^ Sorry KD20, Rant not directed at you