def relative_tuple_path(path_orig, path_dest):
    """Takes two path as list of ids and return a new path that is the
    relative path the second against the first.
    """
    path_orig = list(path_orig)
    path_dest = list(path_dest)
    while (path_orig and path_dest) and path_orig[0] == path_dest[0]:
        path_orig.pop(0)
        path_dest.pop(0)
    result_path = ['..'] * len(path_orig)
    result_path.extend(path_dest)
    if not result_path:
        return ['.']
    return result_path
