Display Book Shelf by Daniel Eatock.

MDF shelf, 6 feet long, 1 foot wide, 3/4 inch thick, resting on two metal brackets displaying books borrowed from Belk Library. The shelf sags under the weight of its contents in a graceful arc, the top edges of all the books are perfectly flush as a result of a conscious selection of volumes chosen to accommodate (or compensate for) the arc of the sagging shelf.

found at dropular