Here is a true story which should get you thinking.
All the staff in the library started to notice that books
were being put upon the shelves in a very random order.
This was not just the normal odd book being put back in the
wrong place,
but whole sequences of books being placed out of order, on,
or around, the shelves they should of been on.
What made this much more mysterious was the fact that it
would happen on various random days, & upon various
random shelves around the library.