Looking at Urban Environments, I went out myself and took some photos.

I think this photo does show the rule of thirds because if you cut them up into 9, then you get something in every single box. In one box, you could get some flowers. In another you could get some shops. And others, part of the car park with some grey sky or the blue stalls. Making the rule of thirds work quite easily.

I think this doesn't show the rule of thirds very well, but you can get 4/5 boxes full. So,  the rule or thirds work because not the sky will be the same, but you'll get some of the roof in the box and some will get some of the plant.  Even if the background is blurry, the rule of thirds would still work.