Strategy: Checkerboard pattern If obsidian is expensive, and you want the most efficient way to defend your base with it, the chequerboard pattern strategy might be suitable for you.   Example design of Obsidian wall.   X   X   X   X X   X   X   X     X   X   X   X X   X   X   X   X = obsidian Open = Stone brick e.g. or another block.+ Example wall: