Here we have two views of a synthetic person formed by merging Sarah and Mark.
You need red-blue 3D glasses to properly view the synthetic person.

The eye with the red filter sees Sarah on the left and Mark on the right.

The eye with the blue filter sees Mark on the left and Sarah on the right.

I find that as I move close to the screen, I tend to see Mark on the left.
As I move away from the screen, I start to see Sarah on the left.
There is an intermediate distance where I see the synthetic person.

The idea for this web page comes from a Scientific American article: "The Resources of Binocular Perception" (Ross01).