3DS technology

I saw how the 3DS technology projects left screen and right screen to the different eyes. It is really very simple to demonstrate. You put on a 3D display, cover the touch screen and shine the upper display (in 3D mode) against a surface in a dark place. I have a picture of what it looks like.

You can see the rays of light forming on the top half of the picture. These are left eye / right eye projections from the 3D display. You can also see that if you hold the display too close, the left/right images will be blended. If you hold the diplay too far away, then one of the eyes will fall into one of the dark bands. If you tilt the 3DS left or right, then the left and right displays will hit the opposite eyes.