Bad code

$n = shift @ARGV;
if ($n == 0) { $n = 6 };

for ($i = 1; $i<$n+1; $i++) {
    # дополнительная оптимизация для скорости
    if (length $current > 0) { $current = $current . '-'; }
    $current = $current . $i;
    $output = "";
    $direction = (($i/2) == int ($i/2));
    if ($direction) {
        @chars = split //,$current;
        for ($k = $#chars ; $k > -1; $k--) {
            $output = $output . $chars[$k];
}
    }
    if (not $direction) {
        $output = $current;
    }
    print "$output\n";
}