The lightbulbs

As they walked along they came by the place where everyone lived. It was something like a dorm and something like a work group and something like a really efficient apartment building. It was like a lot of different things because, on closer inspection, the rooms were all different. Many of them had the doors open. They were different sizes and very different styles. Even the doors were different dimensions and colors. But the most important thing we noticed at the time was the difference in the amount of light that came from each room.
This was important because, as we looked in each room, we saw that some of them had those two-bulb overhead fixtures. They were all supposed to have them, but only some of them had two bulbs and the milky square cover. Some had less nice covers. Some had really dirty ones. Some had bare bulbs and some had only one bulb. There were different ones with different brightness. For the most part, though, they all had some kind of overhead light.
But there was one that didn't, at least they only saw one that didn't.
We investigated the dark looking room. There wasn't a cover, lightbulbs or even a fixture. There was just a hole in the ceiling. There might have been wires hanging down but we couldn't tell.