A hexagon is a six-sided polygon. Several special types of hexagons are illustrated above. In particular, a hexagon with vertices equally spaced around a circle and with all sides the same length is a regular polygon known as a regular hexagon.
Given an arbitrary hexagon, take each three consecutive vertices, and mark the fourth point of the parallelogram sharing these three vertices. Taking alternate points then gives two congruent triangles, as illustrated above (Wells 1991).
Given an arbitrary hexagon, connecting the centroids of each consecutive three sides gives a hexagon with equal and parallel sides known as the centroid hexagon (Wells 1991).