裏うら合あわせ

na-adjective, noun

fitting back to back; agreement of minds

Used both literally for placing objects back to back and figuratively for two people's thoughts or feelings matching perfectly. The figurative use is somewhat literary.

• 二人ふたりの意い見けんは裏うら合あわせのように一いっ致ちした。

  Their opinions matched as if placed back to back.

• この箱はこは裏うら合あわせに重かさねて収しゅう納のうできる。

  These boxes can be stacked back to back for storage.