Reminds me of Marathon's non-euclidean maps. The engine traversed adjacent portals to determine what polygon-based cells to draw/interact with. Very mind bending in its day. Some of the multiplayer maps make strong, obvious use of this, if memory serves.
Duke Nukem 3D had a stock level (E2L11, "Lunatic Fringe") that did something similar. The main structure of the map was a 720-degree loop. I remember it took me a good long while to figure out what was going on the first time I played it.
The other day I was working on my wolf 3d game clone when I noticed this cool bug.
My maps for the game are defined as an object with width, height and an array of arrays for the data. When working on a map that was supposed to be 14 in width and 16 in height, I forget to update the values (8 x 8) and end up creating a infinite level.
Did you walk for 3 minutes? I need to try that. I was walking for a long time and noticed that the maze repeated for as long as I was walking; but I did not time it.
I think it has wrong perspective culling. Seems like the rays are not properly clipped in the view plane so it appears like the view has a "fish eye" effect.
In fact, apparently the entire series is open source and free to play: https://store.steampowered.com/app/2398450/Classic_Marathon/
Highly recommend checking it out.