# ...snip
  my ($n,$i,@n,@temp,%arrangements);
  # get size and create all permutations (comma separated)
  $n = 8;        @n = (1..$n);
  $i = 0;        $temp[&_fact($n)-1] = 1; # _fact := n!

  $|++;
  permute { $temp[$i++] = join(',',@n) } @n;
  print STDERR scalar(localtime),$/;
  @arrangements{@temp} = undef;
  print STDERR scalar(localtime),$/;