I remember this fondly enough to do it again. Fascinating. It is how film, photography, light, lens, and the eye works. Light hits the retina focused by the lens of the eye aided with or without the eyeglasses we wear. It hits as an upside down image. The brain translates and the world is right side up. After all gravity must have its due.
Camera obscura. Yes, full sized. You walk inside. The image appears on the back wall. It is indeed upside down. I righted it. And out of focus – it is because the lens is small relative to the wall behind me. Hey! I got a photograph of the whole thing. I love it when science works. Shamelessly, I am posting this again. It was so much fun the first time around.