Given, say, a hexagon, we can construct a new one by the following procedure.

- find the point where the line determined by
points 1 and 3 intersects the line determined by
points 2 and 4.

- find the point where the line determined by
points 2 and 4 intersects the line determined by
points 3 and 5.

- etc.

Of course, there's nothing special about hexagons. We could make the same construction, in the same way, for any polygon. On an octagon, we would call this construction the octagram. On a 10-gon, we would call this construction the 10-gram And so on.