#!/usr/bin/perl
$foo = 'bar';
$baz = 'qux';

##</code><code>##

#!/usr/bin/perl
use strict;
$main::foo = 'bar';
$main::baz = 'qux';

##</code><code>##

#!/usr/bin/perl
use strict;
$main::foo = 'bar';
$main::baz = 'qux';
$main::foo .= $main::bza;

##</code><code>##

#!/usr/bin/perl
use strict;
use vars qw/ $foo $baz /;
$foo = 'bar';
$baz = 'qux';
$foo .= $bza;