During the year-end party of my daughter's scout group, we have prepared a small workshop for children and adults on pinhole photography. We usued a small cardboard box blackened inside, with a small rectangle of copper paper, on which we made a small hole to create the camera lens. In the darkroom we applied the photo paper inside. The participants left the darkroom heldi a finger over the hole to prevent the light from entering. Then we developed the photo and ... ta-dah! it worked!