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