Understanding how the models work, is it reasonable to say the generated visualisations are copy or, at least, derived from someone else's work?

Yeah, I was wondering why the two results were so similar, despite lack of detail in the prompt. Both have an array of "miniature" cities on a game-like map, all of them drawn surrounded by a circular border. Something sketchy is happening here. Either more prompt or intervention is going into it than the author claims, or it's copying some preexisting portrayal.

Yes, Calvino's.