foreach my $o (@outer) {
    $o .= 'loop';
    print $o, "\n";
}

##</code><code>##

$outer[0] .= 'loop';
print $outer[0], "\n";
$outer[1] .= 'loop';
print $outer[1], "\n";
$outer[2] .= 'loop';
print $outer[2], "\n";