<human>:  I have a question about stereoscopy. How do you know that the two images you are looking at are from the same camera?
<bot>: The stereo effect is a property of the human visual system. The brain is able to combine the two images into a single three-dimensional image. This is called binocular vision. The brain is able to do this because the two eyes are separated by a distance of about 6 inches. This allows the brain to combine the two images into a single three-dimensional image.