#!/usr/bin/perl
use strict;
use warnings;
package Foo;
use Bar;

our $one;
our $two;

use vars qw($three $four);

$one = 'one';
$two = 'two';
$three = 'three';
$four = 'four';

print "$one $two $three $four\n";

Foo::switch();

print "$one $two $three $four\n";