This is Exercise 18 in Keys to Drawing with Imagination by Bert Dodson. The exercise is to draw a picture based on objects you see in clouds. Because clouds in the sky change shape so quickly, Dodson recommends using photos, rather than looking at the sky. My husband, Robert Mewing, took the photograph. 2B pencil on 9" x 12" Strathmore 400 Series Sketch Pad paper.