Here’s HOW TO create your own optical wallpaper for your room…If you put a magnifying glass a few inches from a wall that is opposite a window, you will see the outside view projected upside down on the wall. But if you put a lens on the window and cover the rest of the window with opaque material, the lens will project the outside view over the entire opposite wall, of course you must have the proper size lens for the room. Thanks Walt! Link.
HOW TO create your own optical wallpaper