def get_local_face_forward_index_from_1(face_up_index_from_1 : int):
    """Given an upward face index, gets the corresponding face index for the horizontal forward-facing face (defined at zero rotation around vertical axis)."""
    index_of_forward = None
    if face_up_index_from_1 == 1:
        index_of_forward = 2
    elif face_up_index_from_1 == 2:
        index_of_forward = 1
    elif face_up_index_from_1 == 3:
        index_of_forward = 1
    elif face_up_index_from_1 == 4:
        index_of_forward = 1
    elif face_up_index_from_1 == 5:
        index_of_forward = 1
    elif face_up_index_from_1 == 6:
        index_of_forward = 2
    return index_of_forward