CrossingPolygon

CrossingPolygon[{p1,p2,…,pn}] gives a Polygon representing all points for which a ray from the point in any direction in the plane crosses the line segments {p1,p2},…,{pn-1,pn},{pn,p1} an odd number of times.

CrossingPolygon[{{p11,p12,…},{p21,p22,…},…}] gives a Polygon from the line segments {p11,p12},…,{p21,p22},….

Examples

Create a crossing polygon from a list of points:

CrossingPolygon[{{0, 0}, {1, 1}, {2, 0}, {0, 1}, {2, 1}}]

Please visit the official Wolfram Language Reference for more details.