void main() {
    Point       p = new Point(1, 2);
    ColorPoint cp = new ColorPoint(3, 4, "green");
    DeepPoint  dp = new DeepPoint(5, 6, 3);

    p.moveAndPrint(1, 1);
    System.out.println();
    cp.moveAndPrint(2, 2);
    System.out.println();
    dp.moveAndPrint(3, 3);
    System.out.println();
  }