heptagonus

例句：

1. 1.The heptagon is a geometric figure with seven sides.
   七边形是一种具有七条边的几何图形。
2. 2. The heptagon is used in geometry to represent the shape of a star.
   七边形在几何学中用来表示星星的形状。
3. 3.The heptagon is often found on buildings and other structures as a decorative element.
   七边形常被用作建筑物和其他结构的装饰元素。