Here's an interesting design that allows you to transform the underside of stairs into an inversely tiered bookshelf. Johan Sandström's d'shelf is a multipurpose storage solution with a hidden mounting system that allows for wall and under-surface placement, allowing you to extend usable storage space into tight, unused spaces. The d'shelf is made of real wood, supporting up to 33 lbs. of your favourite books, music, collectibles or whatever else that needs some shelf real estate. A d'lovely idea.