I will here propose you $9$ ways to sort $18$ books. Those books remain the same. For each $9$ ways you have to tell why this is a sort over this books. Meaning:
- There is no Bookleft > Bookright > Bookleft
- There is no BookA left = BookB left > Bookright (Bookleft is always greater than Bookright)
Some ways are very easy to find out, some are very tricky. You are not intended to find all (without this being forbidden haha). If you found one or just a few you can add an answer, just check it wasn't already told, and if so, do not hesitate to +1 the writer's answer or cite him :p.
This is a Lateral-Thinking Puzzle, so I did sort my books in certain ways, but it is possible, that you find other definition that match my sorts, as long as you can justify and that is a clear sort as previously defined, it is perfect :)
There is an icing on the cake at the end!
Sort 1
Sort 2
Sort 3
Sort 4
Sort 5
Sort 6
Hint - 12th May 2020
Colors related
Sort 7
Hint - 12th May 2020
Apart for the books' order, there is something different from this picture.
Hint - 21th May 2020
You may need all other books' pictures to find this one!
Sort 8
Hint - 12th May 2020
Numbers related
Sort 9
Hint - 12th May 2020
Alphabet related
Meta Sort
It's not a sort on the books, but the idea of a meta sort came in comment, from @JMP, and I thought it'd be a good idea adding it to the puzzle. Could you define a meta sort on all the 9 sorts, how are they sorted within themselves? That will be another part of the puzzle when all the 9 sorts will be found!
Icing on the cake
There are two books that can't be easily identified. The big red one and the thin light blue one. The icing on the cake, consists, thanks to the nine sorts, to find which books they are. I'm just curious to know if someone will succeed. It's not properly part of the puzzle, I'm not even sure this is possible without knowing the books :)
Hints and selected answer
I've added some hints (12th May of 2020) for remaining sorts. I've decided to give someone a selected answer based on the following points system:
- 1 point per sort firstly discovered before 10th May 2020 (one month before puzzle release)
- 2 points per sort firstly discovered after 10th May 2020
- 5 points for finding meta sort first and 5 points for icing on the cake first.
- Selected answer given when all 9 sorts discovered and selected answer will adapt after that, depending on standings.
I created this point system with my own opinion on this puzzle hardness but if you have any suggestions to edit it, don't hesitate adding a comment. Ties will be untied with icing on the cake more important to solve, then meta sort, second more important to solve.
Current standings are - 12th May:
1. user65284 - 2 points (draw) Glorfindel - 2 points
3. Gareth McCaughan♦ - 1 point
"cerzvre nzbhe" "rager znvagf" obbx
;) $\endgroup$