Book-building

My wife just put up a set of bookshelves in our basement using books themselves as the building blocks.  I thought this was a bit odd since it makes some of the books a little harder to get to but, on the other hand, it increased the amount of books that could be stored in that space.  And it looks kind of neat.  Now I see that it isn't really odd at all; it's "cutting edge:" we are part of a larger trend using books for building.