sub zipn {
    local $[ = 0;
    [
        map {
            my $index = $_;
            map {
                defined($_[$_][$index]) ?
                    $_[$_][$index] :
                    ''
            } 0..$#_
        } 0 .. maximum(map { $#{$_[$_]} } 0..$#_)
    ]
}

sub maximum {
    local $[ = 0;
    ($#_ == 1) ?
        (
            ($_[0] >= $_[1]) ?
                $_[0] :
                $_[1]
        ) :
        maximum(maximum($_[0], $_[1]), @_[2..$#_]);
}