[ dip nested
    reverse
    witheach
      [ of i if nested ] ]       is array  (     [ --> a )

  [ witheach peek ]              is [peek] (   [ a --> x )

  [ dup dip
      [ rot dip
        [ -1 split drop
          witheach
            [ dip dup peek ] ] ]
    reverse
    witheach
      [ dip swap poke ] ]        is [poke] ( x a [ --> a )