Polygon

public defstruct Polygon <: Shape :
  points: Tuple<Point> with: (ensure => min-length!(3))
with:
  constructor => #Polygon

public defn Polygon (pts:Seqable<Point|Seqable>) :
  val pts* = to-tuple(flatten-shapes(pts))
  ensure-points(pts*, "polygon")
  #Polygon(pts* as Tuple<Point>)

Polygon([
  Point(2.0, 2.0),
  Point(-2.0, 2.0),
  Point(-2.0, -2.0),
  Point(2.0, -2.0)])