#! /usr/bin/perl

use strict;
use warnings;

my @a;
my $b = "abefcdghijklmn" ;

$a[0]->[0] = "start 0" ;
$a[1]->[0] = "start 1" ;

for(my $i = 0; $i < 14; $i += 2) {
    my ($foo, $bar) = unpack("x$i A1 A1", $b) ;
    push @{$a[0]}, $foo;
    push @{$a[1]}, $bar;
}

foreach ( @{$a[0]} ) {
    print "$_\n" ;
}