Elements of Photography:
Two-dimensional representation of objects.
Shape is a two dimensional representation of an object. Kids draw primarily using the shapes like an outline of a farmhouse, a tree, sun, etc. The outer line of an object forms the shape.
In photography, you can represent interesting shapes of the objects by using silhouette effect due to backlighting. Silhouette photographs make an impact when the shape of the subject (object) is clearly defined in contrast with the background.