I find myself writing about light a lot. Especially diffuse half-light, like twilight or moonlight or the light of a single candle. Or the transition of light through the day. Or someone opening a door or curtains and changing the light in the room, which definitely has symbolic meaning, but I don't always intend for it to be there.

I also end up setting things in the autumn frequently, transitioning into winter, which does have an effect on the quality of light. Autumn/winter light is that diffuse light. I think I might just like writing about interstitial places and threshholds and things that are neither one thing or the other. Like in the novel I am writing, a lot of it takes place on an airship traveling between countries that are traditional enemies, and one of the reasons the airship captain has that career is because it means he can make a home in the air and not have to become "rooted" in the soil of either country. That isn't something I intended to write about when I started off, either.

(Ha, my novel. Oh, self. I feel like I should be wearing a cardigan with leather patches on the elbows and using an NPR voice. You know, while talking about the dirigibles. *snort*)

I write about difficulty sleeping a lot, too, but I think that's just because I have insomnia and when it becomes obvious that I'm not going to sleep, I write. That's totally me writing what I know. :P