Union Command

Union( <List>, <List> ): Joins the two lists and removes elements that appear multiple times.

Union( {1, 2, 3, 4, 5}, {3, 2, 1, 7} ) yields {1, 2, 3, 4, 5, 7}.

Union( <Polygon>, <Polygon> ): Finds the union of the two polygons. Works only for where the polygons are not self-intersecting, and where the union is a single polygon.