About 50 years ago, I read a science fiction short story that I'm trying to find today. As best I can remember, it was about a guy who was driving along and the road just ended in front of him. There was nothing past that point, and by nothing, I mean NOTHING! No road, no sky, no trees, NOTHING!
He discovered that he was just an electrical impulse in a computer created by a higher world. The computer was created as a cross-section simulation of a large population, so that they could experiment to see how "normal" people would react to certain stimuli.
Somewhere along the way, we find out that the "higher world" was just another computer that had been created by an even higher world who was stunned that their computer simulation had built their own computer simulation!