DB<112> for $aref ( [1,2,3],[4,5,6],[7,8,9] ) { 
                      $lookup{$aref} = $aref; 
                      $hash{$aref}   = [ reverse @$aref ]; 
                      }
 => ""

  DB<113> \%hash
 => {
  "ARRAY(0xa547e40)" => [9, 8, 7],
  "ARRAY(0xa5c2e68)" => [6, 5, 4],
  "ARRAY(0xa5c3188)" => [3, 2, 1],
}

  DB<114> \%lookup
 => {
  "ARRAY(0xa547e40)" => [7, 8, 9],
  "ARRAY(0xa5c2e68)" => [4, 5, 6],
  "ARRAY(0xa5c3188)" => [1, 2, 3],
}

  DB<115> print "@{$lookup{$_}}\n" for keys %hash
7 8 9
4 5 6
1 2 3