The game "Tea for God" (https://www.google.com/search?q=tea+for+god&oq=tea+for+god) also has this strange behavior where the world curves around in a non-Euclidean / M.C. Escher-style fashion so that you feel like you're in a labyrinth, but you're actually in a ~8ft square in your living room.
"Tea for God" and "Unseen Diplomacy" are the only games I'm aware of that operate in this fashion, with "realistic" walking movement that doubles back on itself.
It uses a trash can plus a super-bright LED bulb plus a plastic book magnifier.
The main trick is that you can get a big magazine-sized flat plastic fresnel lens for like 10 bucks.
The original poster's solution is definitely better, but it's also possible to do this on the cheap with no 3D printing (or in fact, any skills whatsoever).
Moonring is indeed absolutely top-notch! There’s a Mac version as well, and it runs on the Steam Deck. It’s definitely a plausible spiritual successor to Ultima IV. I’m shocked that the existence of an absolutely free game in this genre hasn’t made more of a splash.
"Tea for God" and "Unseen Diplomacy" are the only games I'm aware of that operate in this fashion, with "realistic" walking movement that doubles back on itself.