To use a shadow to enhance your artwork; tell a story; or even interact with your viewer;
To create your own "shadow" photography by setting up items to photograph, going outside and looking for natural shadow art in the world, allowing someone to interact with the shadow, or even allowing the shadow to interact with the world.
water bottles
I was sitting eating my breakfast when I noticed the sun was shining through my window and made a cool colorful shadow, so I grabbed the other water bottles and filled them up and took the picture
rusty
my dog was sitting on my porch and I noticed that the railing made an interesting shadow over his shadow.
army guys
When I went inside I was experimenting with artificial light, and I found some old army toys from when I was little and kept changing up the angle of the light until I got what I wanted