Build Your Own Pinhole Camera

Clever you! That was, of course, the correct answer!
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The number one stands upside down and left and right are reversed compared to the top piece on the torch. By the way, in pinhole cameras the cardboard with the pinhole is called aperture, just like in a normal photo camera, and the transparent paper on which the image appears is called a screen. If you wonder how a paper tube with a pinhole can create an image, you should take a look at the picture below. The course of the light rays is drawn into the picture and will help you understand this principle.

The human eye is based on a very similar principle. The pupil in combination with the iris works like the aperture. You could say the pinhole resembles the pupil and the rest of the black cardboard resembles the iris. The retina in our eyes works like a screen. The images that are created on our retina are also upside down and left and right are reversed. The optic nerve receives the information from the retina and sends it as a nervous signal to the brain. There the signal is processed and the brain makes sure that we perceive the world upright and left things on the left and right things vice versa. A very simple depiction of what happens in our eyes you can see here (many is left out, e.g. how our lens works):