>>>Ok, so it's got three volumes and four covers, 3*3+4*1=13
>>
>>The correct answer, as you probably already read in the other threads, is 7.
>
>My books are most probably not in that order, or in any particular order :).

When the book is on the shelf, page 1 is one the right (of the leftmost book). The last page of vol 3 is on the left. 2 of the books don't get their pages eaten.

>Sounds like this one:
>
>It's big, black and three-legged, hangs from the ceiling. What is it?

A ceiling fan?