p1 = Point(10, 8)
    p2 = Point(50, 20)
    print('p1: Should print  Point(10, 8):', p1)
    print('p2: Should print  Point(50, 20):', p2)

    p1.move_by(5, -1)
    p2.move_by(0, 0)
    print('p1: Should now print  Point(15, 7):', p1)
    print('p2: Should now print  Point(50, 20):', p2)

    p2.move_by(200, 0)
    print('p1: Should still print  Point(15, 7):', p1)
    print('p2: Should now print  Point(250, 20):', p2)

    p2.move_by(-100, 300)
    print('p1: Should still print  Point(15, 7):', p1)
    print('p2: Should now print  Point(150, 320):', p2)