How to Build a Round Tower in Minecraft Round towers look impressive because the circle does the hard work. Pick an odd diameter - 11 is a great all-rounder - and lay the outline at ground level. Build the walls straight up from that outline, adding a window every few layers, and the tower will stay perfectly round all the way to the roof. For the roof, stack shrinking circles on top of each other: reduce the diameter by two blocks every one or two layers until you reach a single block, then cap it with a slab or a fence post. A diameter 11 tower usually takes a diameter 9, then 7, then 5, then 3 circle for a clean cone. Interior tip: a hollow tower of diameter 11 leaves a 9-wide room inside, enough for a staircase hugging the wall with a storage column in the middle. Plan your own circle here: CircleCraftLab