You can leave it as is or go for some more realism by gluing some toys, bookends, or even a fake drink to the bottom of the board to complete the look...
The inverted bookshelf turns a bit of your living room upside down as it hangs all of the books from the bottom instead of supporting them from below. It's a satisfying optical trick and doesn't damage any of the books. In fact, you can take books in and out of it whenever you want.
Step 1: Materials
In addition to the basic materials for a shelf of wood and brackets, you will also need elastic webbing and a staple gun. The elastic that I'm using here can stretch beyond 200% of its original size and is certainly strong enough to hold the books here.