Sort a list of 2D points in anticlockwise order
    :param pps: List of points to be sorted
    :return: Sorted list of points

def anticlockwise_sort(pps):
    """
    Sort a list of 2D points in anticlockwise order
    :param pps: List of points to be sorted
    :return: Sorted list of points
    """
    newpps = list()
    angles = np.zeros(len(pps), np.float)
    for ipp, pp in enumerate(pps):
        angles[ipp] = np.arctan2(pp[1], pp[0])
    iisorted = np.argsort(angles)
    for ii in range(len(pps)):
        newpps.append(pps[iisorted[ii]])
    return newpps