Perl: Array of array

1. Array of array

#!/usr/bin/perl -w
use strict;
use Data::Dumper;

my (@all, @aoa, @all2, @all3, @all34, @aoa2);

while (<DATA>) {
    chomp;
    @all = split;
    push @all34, $all[2], $all[3];
    push @aoa, [$all[2], $all[3]];
    push @all2, $all[2];
    push @all3, $all[3];
}
push @aoa2, (\@all2, \@all3);

print Dumper (@all34);
print Dumper (\@aoa);
print Dumper (\@aoa2);


__DATA__
a   1   2   3   4   5
b   3   5   6   6   8
c   1   5   5   5   7
d   4   2   6   7   9

Output:

$VAR1 = '2';
$VAR2 = '3';
$VAR3 = '5';
$VAR4 = '6';
$VAR5 = '5';
$VAR6 = '5';
$VAR7 = '2';
$VAR8 = '6';
$VAR1 = [
          [
            '2',
            '3'
          ],
          [
            '5',
            '6'
          ],
          [
            '5',
            '5'
          ],
          [
            '2',
            '6'
          ]
        ];
$VAR1 = [
          [
            '2',
            '5',
            '5',
            '2'
          ],
          [
            '3',
            '6',
            '5',
            '6'
          ]
        ];