use Data::Dump::Streamer;
@a_1 = ();
@a_2 = ();
@a_3 = ();
@a_4 = ();
@a_a = (\a_4, \a_3);
@a_b = (\@a_2, \a_a);
@a_final = (\@a_1, \@a_b);

Dump(\@a_final);
__END__
$ARRAY1 = [
            [],
            [
              [],
              \do { my $v = 'a_a' }
            ]
          ];