Thank you :) I'll probably post the decorated hoods sometime next week.

Those are indeed Numenor's objects. It does matter how you place them, as if you place them backwards they'll spray into the mountainside instead of the right way around. I've also found that they don't start spraying immediately. It can take a while before they kick into action, and I haven't found anything that will force them to start. Switching neighborhoods and going in and out of houses occasionally work, but I think it's just a matter of patience, mostly.