def hips_square(x, y, max_slope=0.1):
    """
    9:"RHip" and 12:"LHip"
    straight line (square hips) would have a slope of 0
    0 - stright
    1 - not straight
    """
    slope = (y[9] - y[12])/(x[9]-x[12])
    if -max_slope <= slope <= max_slope:
        return slope, 0.0
    else:
        return slope, 1.0