fn apply_cube_delta(
    (start_y, start_x): (usize, usize),
    start_facing: Facing,
    (wrap_y, wrap_x): (usize, usize),
    face_size: usize,
    face_map: &HashMap<((usize, usize), Facing), ((usize, usize), Facing)>
) -> (usize, usize, Facing)