for my $a (0..@a) {
  for my $b (0..@b) {
    for my $c (0..@c) {
      for my $d (0..@d) {
        for my $e (0..@e) {
# Build a hash with the permutation as the key, and the
# number of zeros as the value
  $permutation{$a[$a].$b[$b].$c[$c].$d[$d].$e[$e]} =
	!$a + !$b + !$c + !$d + !$e;
}}}}}

# Now sort according to the number of zeros
return sort {$permutation{$a} <=> $permutation{$b}} keys %permutation;

##</code><code>##

return sort {$permutation{$a} <=> $permutation{$b} ||
             $a cmp $b} keys %permutation;