package Animal;
package Sheep; @ISA = ('Animal');
package Cow; @ISA = ('Animal');
package Pig; @ISA = ('Animal');

##</code><code>##

sub make_animal
{
    my ($sound) = @_;
    if ($sound =~ /baa/)  { return Sheep->new; }
    if ($sound =~ /moo/)  { return Cow->new; }
    if ($sound =~ /oink/) { return Pig->new; }
}

##</code><code>##

package Sheep;

BEGIN {
   our %::animal_sounds;
   $::animal_sounds{'baa'} = 'Sheep';
}

##</code><code>##

sub make_animal
{
    my ($sound) = @_;

    foreach my $sounds_like (keys %::animal_sounds)
    {
       if ($sound =~ /$sounds_like/)
       {
          return ($::animal_sounds{$sounds_like})->new;
       }
    }
}