I stepped on the stone circle beyond the light-arch door. After I warped, I walked down a dark corridor into a well-lit round chamber much larger than the Hall of Riddles. Every inch of its walls was covered from the floor to twice my height in mirror panels, though they didn't quite extend to the ceiling.
It was by far the most eerie place in the Library, made all the more so that I didn't seem to be reflected by any of the panels. I kept going further in, and by the time I reached the center of the room, I saw that I did have a single mirror image, only in the panel directly in front of me.
I stopped walking forward, trying to get a better look, but after a few seconds, I noticed my reflection had kept going. Not just that, but I was still hearing footsteps clacking off the hard floor of the chamber.
