That is why I said "ancients", endso. The "painted ceiling" idea dates at least to ancient Greece. You may also notice that I deliberately avoided mentioning flat earth, since that the earth is round had been known already to ancient Egyptians.

To me, the word "simulation" implies a deliberate execution, for the purpose of research or entertainment. It is bound to be not perfect. Loops, leaks, deadlocks, crosstalk, crashes are expected. As whoever runs the simulations finds and fixes those bugs, the entities within the simulation may stop experiencing them until a higher level (or simply a newly introduced) bug is exposed.