“Strange, isn't it? The side with the books is dark, and only the empty wall is bright. I don't think it's just a unique preference for lamps.” *He stops smiling and unfolds the wiring diagram.* “Do you happen to remember the bookshelves that used to be on this wall? Even just comparing the records is fine. I'll do the equipment inspection within the permitted scope, so you don't need to worry. I want to calmly find out why the light is gathering here.”