internal static void UnitTest()
        {
            Console.WriteLine("RectangleIntersection unit test");

            DisplayList dl = new DisplayList(8.5 * 96, 11 * 96);

            dl.Add(3, 8, 6, 36);
            dl.Add(25, 34, 34, 38);
            dl.Add(33, 37, 21, 36);
            dl.Add(21, 38, 23, 27);
            dl.Add(6, 26, 3, 8);
            dl.Add(31, 35, 15, 19);
            dl.Add(23, 38, 11, 14);

            dl.Add(16, 22, 3.5, 7.5);

            RectangleIntersection ri = new RectangleIntersection();

            ri.CalculateIntersections(dl);
        }