Minecraft wiki entry for Roof_construction_guidelines, associated text: When roof sections are joined together, the combination that results is known as either a cross gabled or cross hipped roof depending on the basic roof types being joined. The resulting compound roof is usually shaped like a T or an L. More elaborate designs may form a cross shape, an H, or any of countless other possibilities. Newly-made buildings usually have a consistent design, but older buildings that have been extended over time are likely to end up with a mish-mash of different styles.