my $x = "Combined: " . $t . $u . "\n";            # before we start
      = "Combined: " . "apple" . "banana" . "\n"; # expanded variables
      = "Combined: apple"      . "banana" . "\n"; # combined first two
      = "Combined: applebanana"           . "\n"; # then the next
      = "Combined: applebanana\n";                # then the last