Sometimes the best way to call attention to an important aspect of the universe you're creating is to create a detail that is at odds with the rest of the world.
It doesn't have to be something that would be out of place in the "real" world. (Yep, totally not going to take for granted the idea that the world in which I exist is categorically any more real than any other.) For example, a lime green armadillo wearing a crushed velvet vest and drinking ice water out of a highball glass would appear mighty odd sitting by the side of the freeway, but you can go a lot more subtle in most cases..
The Citadel is an invented city, a place that was built for a singular purpose in a short amount of time at huge expense. I've made sure to carefully exclude details that would be at odds with this - the warming of a face under the sun, or a secret meeting by moonlight. But the fact that Jolorn sits behind perhaps the only wooden piece of furniture in the whole place says a lot - both about the environment, and about the man.