This is a small redstone firing range...its not the most beautiful, but its good for killing things fast. Except chickens. It took me forever to kill the chickens. They're so dang short. You will have to put in on the ground, not in midair. This is very useful if you want to add on to it to make a mob grinder, or if you want to teleport someone in the fenced area to kill them. Just flip the switch, and kill away! Note: I made the schematic while standing in back of the device, so take that into consideration when loading the schematic into your world.

If you want to check it out, its on my server.