public static void main(String[] args) {

	  System.out.println("Test 1 :");
	  Rectangle rect = new Rectangle(12.5, 4.0);
	  System.out.println(rect);
	         System.out.println();
	  System.out.println("Test 2: ");
	  // the type of rect1 is ColoredRectangle
	  // the object contained in rect1 is of type ColoredRectangle
	  ColoredRectangle rect1 = new ColoredRectangle(12.5, 4.0, "red");

	  System.out.println(rect1);
	  System.out.println();
	  System.out.println("Test 3 :");
	  // the type of rect2 is Rectangle
	  // the object contained in rect2 is of type ColoredRectangle
	  Rectangle rect2 = new ColoredRectangle(25.0/2, 8.0 / 2, newString("red"));
	  System.out.println(rect2);
	  System.out.println(rect1.equals(rect2)); // 1.
	  System.out.println(rect2.equals(rect1)); // 2.
	  System.out.println(rect1.equals(null)); // 3.
	  System.out.println(rect.equals(rect1)); // 4.
	  System.out.println(rect1.equals(rect)); // 5.
	}