sub Clone2 {
    my $self = shift @_;
    my $matrix = $self->Matrix;
    return Matrix->new(
        "Matrix" => [ map{ [ @$_ ] } @$matrix ]
    );
}

##</code><code>##

sub Clone3{
    my $self = shift;
    bless { "Matrix" => [ 
        map{ [ @$_ ] } @{ $self->{Matrix} } ] 
    }, 'Matrix';
}