Try building a project while looking only in a mirror. You can see
everything but forward is back.
At the Brain Expo there was a star to copy by just looking in a mirror.
It is harder than you think.
Cheshire Cat
Sit near a white wall and hold a mirror between your eyes
so that you look at a person with one eye and you see the wall with
the other.
Wave your hand and part of their face seems to disappear.
Looking at the person with the mirror is interesting also.