static L<DoublePt> lambdaMapLike graphAsPolygon(IF1<Double> formula, int w, int h) {
  new L<DoublePt> points;
  points.add(DoublePt(0, 0));
  for x to w: {
    double y = formula.get(doubleRatio(x, w))*h;
    points.add(DoublePt(x, y));
  }
  points.add(DoublePt(w-1, 0));
  ret points;
}