This kind of reminds me of a plot element in Stephenson's "Fall; or, Dodge in Hell". Main character dies, consciousness is uploaded to a computer where he kind of becomes a God. He makes his own world, manifesting the "firmament" (has anyone else noticed that Stephenson loves the word "firmament", not just in this book).<p>But he creates all this land, and eventually new consciousnesses are uploaded to the same realm and one of the guys was a geologist. He realizes everything isn't real because something like "it's impossible for this type of a mountain to be next to this type of river".
Also check out the follow up: <a href="https://nickmcd.me/2023/12/12/meandering-rivers-in-particle-based-hydraulic-erosion-simulations/" rel="nofollow">https://nickmcd.me/2023/12/12/meandering-rivers-in-particle-...</a>