This is a novel idea for a book case (pun certainly intended), metal rectangular frames that you hang from a pole (the probably sounds stranger than it looks).
The idea behind them is simple, each square holds about 6 books (or 2 Harry Potter’s) where the base of the book rests on the bottom of the square whilst the back rests against a bar at the back (thus preventing it from resting in a pile on the floor). As your book collection grows you simply get more book hangers and hang them on to each other. A very novel approach to book storage.
[Designed by Unal and Boler found via Inhabitat]