As I watched my children playing outside in today's nice, springtime weather, I noticed my shadow laid out on the ground in front of me. My mind wandering as it does, I began studying the contours of this naturally occurring silhouette and something about it struck me as interesting.
When drawing, artists resort to making an average of features in order to make simple, clear statements on their percieved rythm in forms. This is what we call gesture (which I hypothesize is ultimately the whole of drawing, that is, progressively smaller applications of gesture.) Surprisingly, I observed typical gestures of form in my shadow that I normally observe in drawings. Something about the slightly diffuse penumbra, the blurring of subtle disruptions in the contour of my shape had recreated the same types of lines I've witnessed in many man made artworks.
It occurred to me that this could be a great way to study rythm in form. In a sense it should be no surprise, as artists have long done something similar in drawing silhouettes to test the effectiveness of their drawn shapes. But to my knowledge, I don't know of anyone who has studied cast shadows of subjects in order to produce reference for averaged rythms of form.
By adjusting the size and sharpness of the cast shadow, it may be possible to obtain naturally produced averages in shape in order to better inform your drawings.