This is a pretty simple guide, it literally only uses 2 different devices! However, it can be used to create a confusing illusion to the player.
Firstly, create a narrow, 1 block wide pathway. In order for the illusion to be smooth, it HAS* to be 1 block. *is strongly reccomended
Next, add 2 teleporters, with 22 blocks in-between(using the 64 scale in grid snap).
Now, go into the settings of the bottom teleporter. Enter the following into the groups.
Now, the top one.
Now that you have that, it’s time for my favorite part, the camera view.
With 3 units open on each horizontal side, bring the edges 4 units from the top and bottom sides of the hall(the hall is 24 units long)
Now fill in the remaining camera view zone with the same terrain as the walls.
Now you have your infinite hallway!
The top teleporter will put the the player back at the start, but the player is still able to exit through the bottom.