use List::MoreUtils qw(part natatime);

sub chunk_array {
    my ($n, @vals) = @_;
    my $str;
    my $iter = natatime($n, @vals);
    while ( my @line = $iter->() ) {
        $str .= join(" ", @line) . "\n";
    }
    return $str;
}

sub chunk_array {
    my ($n, @vals) = @_;
    my $i = 0;
    return join "", map { join(" ", @$_)."\n" } part { $i++/$n } @vals;
}