The books he’d brought with him from Privet Drive were arranged within; they barely filled one section of one shelf. Harry started adding the books he’d purchased at Flourish and Blotts. When he ran out of room, he pulled one of the handles to the right, and the entire bookcase slid to the side, revealing more empty bookshelves (with no carvings, he noticed). He put the last few books on these shelves, watching as figures started to appear in the woodwork (perhaps they were drawn from the books shelved there?), then pulled to the right again. The first shelf slid in again, as though the entire bookcase were a lazy Susan.