A prism is named by the shape of its polygon cross-section. When the cross-section is a triangle, the prism is called a triangular prism. When the cross-section is a hexagon, the prism is called a ...

The polygon shape of the cross-section may be used to name the prism. A prism with a triangle-shaped cross-section is a triangular prism. A prism with a pentagon-shaped cross-section is a ...

A cross section of a chambered nautilus shell shows the newly defined shape, the "soft cell," repeating ... which is one less than the triangle—it is a very special kind of tiling.” ...