As most of you probably know by now, one of the bonus funding goals for the New Worlds Patreon covers a fifth post in the months that have five Fridays. For these “theory posts,” I step away from the specifics of what goes into a world, and instead look at more abstract matters: either techniques of handling this stuff in writing, or anthropological concepts of use in worldbuilding. This month is one of the latter, with the idea of cultural spheres. Comment over there!