See through hand

I used to put my hand over one eye , and tell my mother I could see through my hand, because as a child that's how it seemed so. I grew older and my mother finally told. She said "Sydney, my dear, your other eye is open too, and that is what you're seeing through."

I didn't believe her for the longest time cause I thought it would still work with the other eye closed, so I tried to experiment, and found it didn't work .