class Rectangle(object):
    def __init__(self, width, height):
        self.width = width
        self.height = height

    @property
    def perimeter(self):
        return 2 * (self.width + self.height)

    @property
    def square(self):
        return self.width * self.height

    def set_width(self, value):
        self.width = value

    def set_height(self, value):
        self.height = value

class Square(Rectangle):
    def __init__(self, a):
        super(Square, self).__init__(a, a)

    def set_side(self, value):
        self.width = value
        self.height = value

    set_width = set_side
    set_height = set_side

if __name__ == '__main__':
    rec = Rectangle(1, 2)
    print 'rec perimeter:', rec.perimeter
    print 'rec square:', rec.square
    rec.set_width(3)
    print 'rec perimeter:', rec.perimeter
    print 'rec square:', rec.square
    
    rec.set_width(5)
    assert rec.square == 10

    sq = Square(2)
    print 'square perimeter:', sq.perimeter
    print 'square sqare:', sq.square

    

    sq.set_width(1)
    assert sq.square == 1
    sq.set_width(30)
    assert sq.square == 900