 All of these rooms and hallways are completely unlit and featureless, consisting of smooth ash-gray walls, floors, and ceilings.The only sound disturbing the perfect silence of the hallways is a periodic low growl, the source of which is never fully explained, although an academic source "quoted" in the book hypothesizes that the growl is created by the frequent re-shaping of the house.There is some discrepancy as to where "The Five and a Half Minute Hallway" appears.