Gnome Farm! As if you need it....

[DeltaKElp]

I think the image explains a how to build it. But it is very important that you build in front of the naturally generated living wood wall , otherwise it will not work. Also it requires to clear perimeter around player: 50 Up and Down, 86 Left and Right, so no other mobs can spawn and Gnomes could spawn only on platform on your right. 5 seconds timers must be synchronized not to break farm. Day and Night sensors will deactivate and activate farm, because Gnomes will not die during Night and kill you if you afk. (safety isn't tested, you might die)

PS, Gnome banner looks kinda creepy...