package Colour {
    use Scalar::Util 'refaddr';
    my %colour;
    sub new {
        my $o = bless \do{my $var}, $_[0];
        $colour{refaddr $o} = $_[1];
        $o;
    }
    sub colour {$colour{refaddr $_[0]}}
};
package Age {
    use Scalar::Util 'refaddr';
    my %age;
    sub new {
        my $o = bless \do{my $var}, $_[0];
        $age{refaddr $o} = $_[1];
        $o;
    }
    sub age {$age{refaddr $_[0]}}
};
package Colour_and_Age {
    our @ISA = qw[Age Colour];
    use Scalar::Util 'refaddr';
    sub new {
        my ($class, $colour, $age) = @_;
        ... Now what? ...
    }
}