Skew polygon

In geometry, a skew polygon is a polygon whose vertices are not all coplanar. Skew polygons must have at least four vertices. The interior surface (or area) of such a polygon is not uniquely defined.

Skew infinite polygons (apeirogons) have vertices which are not all colinear.

A zig-zag skew polygon or antiprismatic polygon has vertices which alternate on two parallel planes, and thus must be even-sided.

Regular skew polygons in 3 dimensions (and regular skew apeirogons in two dimensions) are always zig-zag.