package foo;
sub x {
	our $bar;  # $foo::bar
	$bar++;
	my $quz;   # a lexical $quz, not accessible outside this sub!
}
sub z {
	our $bar;  # the *same* $foo::bar
	$bar++;
	my $quz;   # a *different* lexical $quz
}
# no $bar here! but:
sub w {
	$foo::bar++;   # still the same $foo::bar
}

##</code><code>##

package bar;
our $DEFAULT_QUZ = "World";
sub hello {
	my $what = shift || $DEFAULT_QUZ;
	print "Hello, $what!\n";
}

package main;
bar::hello();          # Hello, World!
bar::hello("Alice");   # Hello, Alice!
$bar::DEFAULT_QUZ = "Bob";
bar::hello();          # Hello, Bob!