I like the concept of this bookshelf which dynamically adjusts
its shape to whatevere you put inside it. The Elastica
Bookshelf, designed by Arianna Vivenzio, is basically a large
elastic bandage stretched around 2 metal posts that are
permanently fixed to the wall.  The design allows you to fit a
variety of different sized objects inside, such as books, CDs,
DVDs, trinkets and even boxes full of smaller items. The shelf
takes a different shape as you change its contents.