Click on the image above to see a larger version, and follow these simple steps: Starting at the room in the northwest corner, move your finger down the hallway to the large room. Head down the first flight of stairs, down the second flight of stairs, and down the third flight of stairs. Now head around the bend, through the archway, and find yourself on the same level as you started from, while remaining walking on a flat surface.
I need to lie down, my brain hurts.
MMO Fallout 