What can be said about the shape of a shadow?
It is similar to the object
The shape of a shadow depends on the shape of the object and on the orientation of the source of light with respect to the object. For example, the shadow of a cube can be rhombus, square, rectangle or no shadow at all depending on the orientation of the source of light. In addition, the size of the shadow will depend upon the distance of object and source of light, size and shape of the object and size of the source.