Minecraft wiki entry for Door-based_iron_golem_farming, associated text: This design, by NimsTV, is less efficient than JL2579's design. However, it is much simpler and easier to build, because the water streams are easier to configure and there is only one villager basket. The golem spawning area is larger than the farm, which is why JL2579 did not build his farm in this way. You have to block spawning anywhere outside the farm, if you intend to build several duplicate farms in an array.