Ancient X-Files: The Mona Lisa Code (Preview)
The following sketches are from Leonardo's journals. They show that he had considered the idea of the superimposition of faces. If you were to change the orientation of the sketches and view them from the front - they would become one image/face. This can be achieved without the use of modern technology... by crossing two images over on each other with your eyes. (The effect is enhanced when it's seen that way due to the alternating left and right eye dominance.)
More @ Itsjustlife.com & "Discovering Da Vinci's Daughter" is coming soon!