例句與造句

1. There are a few non-Wythoffian uniform polyhedra, which no Schwarz triangles can generate; however, most of them can be generated using the Wythoff construction as double covers ( the non-Wythoffian polyhedron is covered twice instead of once ) or with several additional faces ( see Omnitruncated polyhedron # Other even-sided nonconvex polyhedra ).
2. It's difficult to find nonconvex polyhedra in a sentence. 用nonconvex polyhedra造句挺難的