Thread:Quaccanthrope/@comment-34703140-20191012005026/@comment-40076885-20191102183526

''As mentioned earlier, they are all murder mystery books by Agatha Christie. It seems as if these books were repeatedly pulled forward and backward.''

The books moved are the 16th book from the left on the first shelf, the 6th and 18th books from the left on the second shelf, the 4th and 9th books from the left on the third shelf, and the 1st and 8th books from the left on the 4th shelf.