^Yeah, they're definitely trying to resemble some sort of basalt formation. They can be found everywhere around the globe in the vicinity of old volcanos. There's actually a place quite close to me with these dark grey/blackish hexagonal rock shapes!
I'm not 100% certain what the theme is yet, but maybe it has something to do with volcanos? Or it's simply just another way of making a rock formation... Love the look of it though <3