tests.json

{
  "input": [
    [
      [
        1,
        2,
        3
      ],
      [
        4,
        5,
        6
      ],
      [
        7,
        8,
        9
      ]
    ]
  ],
  "want": [
    [
      1,
      2,
      3,
      6,
      9,
      8,
      7,
      4,
      5
    ]
  ]
}