class Rectangle:
    """
    Rectangle represented with location and size
    """

    def __init__(self, x1, y1, x2, y2):
        """
        Construct a rectangle based on two corners:
        (x1, y1) and (x2, y2).

        :param int x1:
        :param int y1:
        :param int x2:
        :param int y2:
        """

        # find the lower left hand corner
        if x2 < x1:
            x1, x2 = x2, x1
            
        if y2 < y1:
            y1, y2 = y2, y1
        
        self.x = x1
        self.y = y1
        self.width = x2 - x1
        self.height = y2 - y1
                
    def area(self):
        """
        Calculate the area of the rectangle.

        :return: the area
        """
        return self.width * self.height
    
    def equals(self, another_rectangle):
        """
        Determine if another_rectangle is equivalent
        to the current rectangle.  A rectangle is equivalent
        if it is at the same x,y location and has the same
        dimensions.

        :param Rectangle another_rectangle: another rectangle
        :return: (bool) True if the other rectangle is equal
        """
        return self.x == another_rectangle.x and \
               self.y == another_rectangle.y and \
               self.width == another_rectangle.width and \
               self.height == another_rectangle.height
    
    def __str__(self):
        """
        Rectangle location and area.

        :return: (str) representing the rectangle
        """
        return "Rectangle at (" + str(self.x) + ", " + str(self.y) + \
              ") with area:  " + str(self.area())
        
        
r1 = Rectangle(0, 0, 10, 20)
r2 = Rectangle(0, -10, 10, 10)
r3 = Rectangle(10, 20, 0, 0)

print(r1)
print(r2)
print(r3)

print("Is r1 equal to r2? " + str(r1.equals(r2)))
print("Is r1 equal to r3? " + str(r1.equals(r3)))