I just started outlining a short class about improvised street art I hope to teach this summer...have to pitch it to Austin Free Skool...so we'll see if it happens or not. But it's fun to think about...
So aside from one's first hand experiences, where does one begin? Because I'm curious about what else exists out there, I just googled "improvised street art" and came across this and a few other things.
In some ways, all street art is improvised....you're not buying a particular pristine canvas, instead you're working with what is there...a wall, a crack, a sidewalk. Even so, I'd like to try to take it more the Andy Goldsworthy route, and see what people come up with when they work with what the natural + urban environment provides them with.
Stay tuned.