p1 = Point(30, 18)
    print('p1: Should print Point(30, 18):', p1)

    p2 = Point(100, -40)
    print('p1: Should still print Point(30, 18):', p1)
    print('p2: Should print Point(100, -40):', p2)

    p1.y = 500
    print('p1: Should now print Point(30, 500):', p1)
    print('p2: Should still print Point(100, -40):', p2)

    p1 = Point(555, 444)
    print('p1: Should now print Point(555, 444):', p1)
    print('p2: Should still print Point(100, -40):', p2)