These are some designs and ideas for an indoor maze.
The first design I came up with was a series of interlinked rooms.
I had the idea that at the exit or entrance to each square (or room) in each doorway there would be a curtain that prevented you seeing what was beyond. So if you stood in each room all you would see in each one is the four curtains. I imagine the room to be plush red Victorian study type rooms all with exactly the same furniture, perhaps a round mahogany table in the centre, a dresser and a bookcase, all in exactly the same location with exactly the same stuff so whatever room you entered it had exactly the same layout. If you wanted to be really difficult you could give the room furniture a 2 or 4 fold symmetry. Of course if you wanted to be devilish you could change one item in each room, perhaps the book title of the third book on the third shelf would always be different, or there would be a silver spoon somewhere different in each room. Each room would not only be part of a larger maze but a sort of Sherlock Holmes esque spot the difference competition.
After this initial design I thought there was still lots of white space and really it could be a lot more of a complex maze.
Iteration 2 of the maze turned into this:
Now this is much more of a maze. Still the same curtains in each room but now when you leave the bright room you enter not just a corridor between rooms but a dark maze of twist and turns lit in shadows as you find your way to the next room. This also has dead ends in the maze so you can get lost, although once you learn the symmetry of the maze it becomes a lot easier.
To add to the darkness visitors to the maze would have torches as the dark areas are barely lit.
There are lots of other variants to the maze, I can imagine actors roaming the maze telling stories to visitors, different lighting effects both in the dark areas and the room. Although I would probably want to stick to the rooms as places of quiet sanctuary and only the dark areas being the scary part. I imagine in the darkness you could have scary footsteps, howls and thunder and lightening, it would be a fantastical yet scary place.
I have also had practical thoughts as well, the entrance would be in the bottom left and the exit in the top right, but an emergency escape route would be a corridor that runs all the way round the outside.