Phone directory.

Just before Alexander Graham Bell made his historic first telephone call to Mr. Watson, he looked for a place to write down the number so it would be convenient if he decided to call again. Ever since, people have been faced with the same problem: where to list frequently called telephone numbers. All sorts of methods have been tried, from writing the number on the nearest wall to entering it into the capricious memory of a home computer. Most of these methods fail because they are unattractive, cumbersome or permanent in a non-permanent world.

The directory is made from a wooden shutter with movable louvers. The movable louvers allow the directory to be closed when …