There are some excellent examples of geometric shapes used in print, they again use the same techniques in previous posts, you will see these here;
Varg Eyewear use the techniques covered in geometric shapes post to promote their glasses and this allows for a fresh looking design that stands out from the crowd.
Outliners use geometric shapes to create a window to the image behind, it creates a simple, clean but interesting front cover, this is something I will consider when designing my printed design.