Below I added the Youtube link in case it works better.
A good friend of mine, Brent Watkinson, http://brentwatkinson.com/landscape/gallery1.php has a wonderful lecture about silhouettes, and our collective recognition of things by their shape, as well as the ambiguity of what we may be seeing because of ambiguous shapes. A silhouette of a rubber ducky can look like a door knob if seen from the front, but turn it sideways and, presto, a rubber ducky! We can’t just turn things sideways to make them obvious all the time, but we can definitely find fun, cool, dynamic silhouettes to help tell our story. Sometimes it may even be a good idea to make a silhouette vague in order to make the viewer participate in the image more. They will fill in the blanks as it were. The main point is to understand shapes and volumes and how they work in your image. You are the director.