This is a fun, almost novice-level construction project for anyone who has a 2-meter ham radio walkie talkie (e.g., the $26 Baofeng UV-5) and would like more effective range without having to buy an amplifier. If you are currently using a short rubber-duckie antenna, this high-gain yagi antenna may well make your radio appear to have 6-10 times its power on 2 meters, doubling or tripling your range in relatively open areas, for a total cost about $21. [Dense high-rise central business city centers may not see as great an improvement, nor areas with impenetrable hills.] That may just make it possible for you to reach useful repeaters or friends from inside your house.
Using thick multi-ply packing/shipping corrugated cardboard to simplify construction (see the accompanying photo of the completed antenna), this antenna is for indoor or very protected outdoor usage only; it has to stay dry. This antenna can be "hung" like a large painting on any wall that "points" it in the right direction, as long as there isn't a lot of metal in the wall, and the house doesn't have metal siding (or buried rebars).
It can even be covered up with a large poster or a world map, and no one will even know it is there!