User:GrayBeard Actual/Notebook/Standard Killtower
Once I have created a decent base/crafting station and have gathered enough resources, especially ammunition, I usually build a kill tower that I use for hordes on 7day.
Each tower has a pit to trap the zombies and a tower in the center with iron bars at the top to shoot through. The iron bars also keep the spiders from reaching me.
Often I will tunnel below the structure for additional resources and to continue to build (increasing xp and skill levels).
I don't build kill towers near my primary base/crafting station to keep those locations hidden from other players and to minimize exposure of those structures to zombies.
I often place forges and fires in the rooms below ground to increase heat and to continue production of items while I defend against the horde.
I will often also place one row of log spikes around the base (in the pit) to keep the zombies away from the tower itself and this also has the added benefit of damaging their legs, slowing them down and making them easier to shoot.