Minecraft wiki entry for Creating_shapes, associated text: The pattern of blocks for every circle cannot be explained, because, like mentioned earlier, each size has a completely different pattern. The best way to make a circle is to just experiment with different block arrangements, or look at images made by other people who experimented with block arrangements and made a circle. The diagrams only show quarter circles; the full circles are obtained by reflecting the quarter-circles along the top and left edges. For circles with odd diameters, reflect along the center of the first line of blocks.