It's creative to use the broken plate to form a tree shape. The negative space is working well in contrasting with the plate. Also, the plate is shattered in the perfect way to create an interesting tree shape out of the dark background.
This book cover shows excellent figure ground/negative space. The contours formed by the position of the fox serve as the shape of a boy, I'm assuming "Peter." This empty space also creates a wonderful focal point for the book title to nestle into.