Camera obscura appears in most upstairs rooms. When the sun is bright outside, close the exterior shutters. On the stone window frame, you will see a hole that the light comes through. It creates a moving image on the wall opposite.

Make the room as dark as possible. The image appears upside down. Experiment with blocking the hole and watch how the images become sharper.

For photography, a phone will see the image, a good camera better. Both create a sharper image than can be seen with the eye, but do not capture the movement. Experiment with night vision, a tripod and long exposure.