#2791: Bookshelf Sorting explain

[A bookshelf hanging on a wall is shown. It is covered almost from left to right but not with ordinary books. To the left there are 11 covers next to each other without any paper between them. They have different heights and shades of gray. After the last of these there follows many leaves of paper of differing heights similarly to that of the covers. The top of the papers thus form a wave shape with more than twenty peaks before they reach another cover. After that there follows similar patterns with paper in different height and then a cover in between more papers. But there is a much shorter distance between the first and second cover than before the first cover, after the initial 11 covers. The next two covers are close to the first, then there is a longer stretch of paper to the fourth, much less to the fifth, and then the next three covers comes very close. There is again quite long distance to the ninth and tenth cover, and here the number of different heights for the paper are clearly less than the previous paper stretches. Finally before the last and 11th cover all the paper, not much of it though, are of the same height, and just a bit lower than the final cover. The 11 covers at the start matches the 11 covers later and they comes in reverse order throughout the paper stretches as they are sorted to begin with, so the first and last cover matches, as does number 2 and the second last etc. There is a caption beneath the panel:]

Book people hate seeing books sorted by colors, but it turns out they get way more angry if you sort the pages by number.