Perhaps you could make up a story. The two of you could even make a book with her "drawing" pictures. Ask her what each mark means and write that down as well as the story you're telling.
Have you checked the public library parenting section. They have book for both the parent and the child. The librarian can help you find one.
Not your question, I know, but it might help to make shadows on the wall with your hands so that she can see how shadows are made. There are books and booklets that shows you how to make different shadow animals.