use Carpet;
use YAML;

my $o = Carpet->new;
$o->width(10);
$o->height(10);
$o->unit_price(1.00);

my $o2 = Load(Dump($o)); # serialisation with YAML
$o2->width(15);
$o2->unit_price(0.85);

$o->display;
$o2->display;
print "difference = \$", abs($o->price - $o2->price), "\n";