Want to mob proof your buildings? Put two stacked perimeters of staircase/slab/wall around the bottom and a roof overhang on top. The overhang keeps spiders, cubes, and phantoms at bay and the perimeter keeps away endermen, undead, and creepers.
Leave slits in your outer structure by replacing solid blocks with stairs or slabs, and put trapdoors in front on either side if you need protection, or set up a piston system on the inside. Then you can snipe Ghasts, Shulkers, and other further away targets with ease
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