#!/usr/bin/perl

use strict;
use warnings;
use Data::Dumper;

my %data = (
        l1 => ['x1', 'x2', 'x3'],
        l2 => ['y1', 'y2', 'y3', 'y4'],
        l3 => ['z1', 'z2', 'z3', 'z4', 'z5'],
        );

my @liste=();
for my $key (sort{ my ($x)=$a=~/(\d+)/; my ($y)=$b=~/(\d+)/; return $x <=> $y}keys(%data))
{
  print "LISTE: $key\n";
  my @l_bak=@liste;
  @liste=();

  if(@l_bak)
  {
    for my $val (@{$data{$key}})
    { push(@liste,map{"$_-$val"}@l_bak); }
  }
  else
  { @liste=@{$data{$key}}; }
}

print Dumper(\@liste);