polymenrism

例句：

1. 1. The octahedron is a simple geometricshape with eight equal sides.
   八面体是一种简单的几何形状，有八个等长的边。
2. 2. Polyhedra are used in variousfields such as architecture and engineering.
   多面体在建筑和工程等领域都有应用。
3. 3. Thestudy of polyhedra is known aspolyhedral geometry.
   多面体的研究被称为多面体几何学。