use strict;

package Foo;
use vars qw( $foo );
$foo = 100;

package Bar;
use vars qw( $foo );
$foo = 200;

package Baz;
use vars qw( $foo );
$foo = 300;

package main;

my $package = (qw( Foo Bar Baz ))[ int rand 3 ];
my $foo = $main::{"${package}::"}{foo};
$foo = ${ *{$foo}{SCALAR} };
print "($foo)\n";