def _extrapolate(x1, y1, slope, x0, x2):
    """
    Extrapolate from pivot point to the ends
    :param x1:
    :param y1:
    :param slope:
    :param x0:
    :param x2:
    :return: tuple containing low and high end points
    """
    y0 = int(slope * (x0 - x1) + y1)
    y2 = int(slope * (x2 - x1) + y1)
    return (x0, y0), (x2, y2)