public void expandToEnclose(Rectangular other)
    {
    	if (other.x1 < x1) x1 = other.x1;
    	if (other.y1 < y1) y1 = other.y1;
    	if (other.x2 > x2) x2 = other.x2;
    	if (other.y2 > y2) y2 = other.y2;
    }