The ones that I used downstairs are spray-painted. They're made out of vinegar gallons. Three colors that call a lot of attention, all around the front. That did bring people to the restaurant. And people took photos of and with them :-)
I wanted to do that with those, too, but then I refrained from it. I personally don't care enough on the rooftop, it's ugly as it is :-D Would need a lot of work to make it nice, and I'm probably moving out soon, so no need.