Question

Use a paper towel/toilet paper roll or roll up some paper like a telescope. Look through it with your right eye placed against a wall or dark surface and put your left hand in front of your left eye. What do you see ? why?

Answer 1

If we look through a paper roll with my right eye place against a wall and put our left hand in front of our left eye then we will see my left hand with a dark spot on it, more clearly the image seems to be a hole in my left hand. This is due to optical illusion. When paper roll placed in our right eye we will see distance through it, while through left eye we will see our hand. Our brain will combine these two responses and makes a single image of these two.