didn't get this to work
I didn't get this to work just playing with it for about a minute but you can do the same thing with two dots on a piece of paper about an inch apart and moving the paper closer and further from your face if I remember correctly.
This blind spot in binocular vision or actually two, one for each eye if I remember correctly, might be what explains some misses on those near straight in shots that should be ducks. We only see monocular vision in spots but we aren't aware of it since our mind fills in the blanks.
Hu