Rubik's Cube Moves

move_names = "RLUDFB"

def allow_adjacent_moves(move1, move2):
    idx1 = move_names.index(move1[0])
    idx2 = move_names.index(move2[0])
    if idx1 // 2 != idx2 // 2:
        # moves are on different axis
        return True
    if idx1 % 2 == 0 and idx2 % 2 == 1:
        # moves are on same axis, but different and in correct order (RL, but not LR)
        return True
    return False

def recursive_gen(target_length, moves):
    if len(moves) == target_length:
        yield moves
        return

    for move_name in move_names:
        if moves and not allow_adjacent_moves(moves[-1], move_name):
            continue

        for count in ("", "2", "'"):
            moves.append(move_name + count)
            yield from recursive_gen(target_length, moves)
            moves.pop()


if __name__ == '__main__':
    for alg in recursive_gen(3, []):
        print(' '.join(alg))