Kelly M. Houle creates some amazing art. Below is a portrait of Walt Disney. It is easy to see the Disney characters in this art but where is the portrait? To see this you must use a cylindrical mirror.
The image is laid down flat and the mirror is positioned. The below photograph clearly shows the portrait of Walt Disney seen in the mirror. This a very interesting technique you can read "How Cylindrical Mirror Anamorphosis Works" on this page.
Go to her site and check out the array of art that she has created.