Now that I think of it, back when I was a kid in the 90s, there was a circa-70s oscillating fan that my family kept in the living room during the summer, and the noise it made was quite pleasant. The oscillation added a gentle rhythmic quality that made it even nicer.

I’d never put two and two together until now, but that fan had to have been a major factor in some of the unexpectedly great naps in that room.