use strict;
use warnings;

use Data::Dumper;

my $string = join q{}, map { int rand 10 } 1 .. 24;

my @AoAofSixes =
   map { [ split m{} ] }
   $string =~ m{.{6}}g;

print Data::Dumper->Dumpxs( [ \ @AoAofSixes ], [ q{*AoAofSixes} ] );