class Point {
  num x, y;
  Point([num this.x = 0, num this.y = 0]);
  String toString() =>
    [this.x, this.y].toString();
}

class Pixel extends Point {
  String color;
  // WHAT HERE?
}

main() {
  [
    Point(),
    Point(2, 2)
  ]
  ..forEach(print);
}