def _quadrant_gt(quadrant, x, y, x0, y0):
    """Return whether y is further along the ellipse than coord."""
    if quadrant % 2 == 0:
        if y != y0:
            return y > y0
        else:
            return x < x0
    elif y != y0:
        return y < y0
    else:
        return x > x0
