public void treblih(T turtle, int n)
        {
            if (n == 0) return;
            turtle.turnLeft(-90);
            hilbert(turtle, n - 1);
            turtle.Forward(10.0);
            turtle.turnLeft(90);
            treblih(turtle, n - 1);
            turtle.Forward(10.0);
            treblih(turtle, n - 1);
            turtle.turnLeft(90);
            turtle.Forward(10.0);
            hilbert(turtle, n - 1);
            turtle.turnLeft(-90);
        }
        private void hilbert(T turtle, int n)
        {
            if (n == 0) return;
            turtle.turnLeft(90);
            treblih(turtle, n - 1);
            turtle.Forward(10.0);
            turtle.turnLeft(-90);
            hilbert(turtle, n - 1);
            turtle.Forward(10.0);
            hilbert(turtle, n - 1);
            turtle.turnLeft(-90);
            turtle.Forward(10.0);
            treblih(turtle, n - 1);
            turtle.turnLeft(90);
        }
        public void Rosetta(int n)
        {
            T turtle = new T(400.0, 400.0, 180.0, g, pen);//30
            double length = 400 / n;
            double angle = 360 / n;
            for (int j = 0; j < 20; j++)
            {
                for (int i = 0; i < n; i++)
                {
                    turtle.Forward(length);
                    turtle.turnLeft(angle);
                }
                turtle.turnLeft(18);
            } 
        }
        public static void koch(int n, double step, T turtle)
        {
            if (n == 0)
            {
                turtle.Forward(step);
                return;
            }
            koch(n - 1, step, turtle);
            turtle.turnLeft(60.0);
            koch(n - 1, step, turtle);
            turtle.turnLeft(-120.0);
            koch(n - 1, step, turtle);
            turtle.turnLeft(60.0);
            koch(n - 1, step, turtle);
        }
        private void Serpinsky(T t, int order, double size)
        {
            if (order == 0)
            {
                t.Forward(size);
                t.turnLeft(120);
                t.Forward(size);
                t.turnLeft(120);
                t.Forward(size);
                t.turnLeft(120);
            }
            else
            {
                Serpinsky(t, order - 1, size / 2);
                t.Forward(size / 2);
                Serpinsky(t, order - 1, size / 2);
                t.Forward(size / 2);
                t.turnLeft(120);
                t.Forward(size);
                t.turnLeft(120);
                t.Forward(size / 2);
                t.turnLeft(120);
                Serpinsky(t, order - 1, size / 2);
                t.turnRight(120);
                t.Forward(size / 2);
                t.turnLeft(120);
            }