To copy an image using reflection.
This is to make a device for copying images and drawings. A glass pane will reflect images like a mirror, especially when the far side of the pane is dark and the other side is illuminated. Place a glass pane to be supported vertically on a table, as shown. Place the image to be copied on one side of the glass, and a sheet of blank paper on the other. Sit on the side of the glass pane where the image is. Make the room dark except for one lamp that shines on the image. The image will seem to fall on the blank paper through reflection. The glass pane will be transparent enough for you to see your hand and pencil through to trace the image.