package Aa;
use Bb;
my $object = Bb->new();

##</code><code>##

package Bb;
use Aa;
my $object = Aa->new();

##</code><code>##

package Aa;
use Bb;
my $result = Bb::some_function_which_does_not_create_object();

##</code><code>##

package Bb;
use Aa;
my $object = Aa::some_function_which_does_not_create_object();