I have always been interested in the idea of focusing light and how it can be done through clear and opaque materials.  While working at my my desk I noticed the reflections coming off of some metal sitting beside me.  This is a simple example of how light can be focused by controlling the direction it reflects off of surfaces.  This way the opaque materials can focus light.  The second image is an example of refraction where light is focused in certain areas.  This is determined by the way the light enters, moves through the transparent material and exits.  This creates a highlighted end of the acrylic, and casting of shadows on the surface of the only in certain areas.  The last image is a shadows being cast by a shredded cardboard packing material, and I found the composition to be quite impressive.