The subject of street art comes up from time to time, often with Starchild. Don't know how much of this was done with the approval of property owners or the "authorities"....but pretty good stuff.
http://www.upliftmag.com/28-pieces-of-street-art-that-cleverly-interact-with-their-surroundings/
Michael
I will go ahead and assume that the property owners were OK with the art. Now I can say, wow, that is really pretty.
I used to drive on Bryant Street on my way downtown once a week for years. Each time I went by, I enjoyed one of these ambient art. There was a small lonely tree growing close to a large wall. On the wall there was painted one of those traffic arrows pointing to the tree, but instead of "One Way" the arrow said "One Tree."
Marcy