Touch index fingers together.
Stretch your arms out in front of you with your index fingers still touching at eye level.
Keep both eyes open.
Look straight ahead and focus on a far point.
Slowly bring your touching index fingers closer in toward the bridge of your nose
What do you see? (It will appear that you grew a sausage between your index finger tips).
How does this happen?
What might happen if you close one eye?
Even though your eyes are focused on a far point, we still see objects that are closer to the eyes. This is the reason why we see only a piece of the finger. What
ever image overlaps is seen more clearly. Optical illusions are the result of
our brains folllowing reasoning to what would apprear to be a logical conclusion. The
image of the two eye retinas have to correspond. Our visual system attempts to
do the best it can, but sometimes it is wrong.