If you want to see, you have to Look.
I wonder if they're prepping the wall for another round of graffiti?
John, sometimes, like here, it might even be more interesting - an early Pollock epigone maybe? Something evolving into post modern cubism? But you clearly framed it as undesirable, and that, in itself, works too.
Many towns collect paint to keep it out of landfills, and then mix it all together to use on city projects. The color is always some shade of gray. Too bad they didn't paint the whole wall. Yes, a form of cubism, and a new canvas for graffiti painters.