my @in  = ( 2, 3 );
my @out = ( 1, \@in, 4 );
my $r   = \@out;
$r = [ 1, [ 2, 3 ], 4 ];
$r->[1]->@*;  # equivalent to @{ $r->[1] }
              # equivalent to @{ $out[1] }
              # equivalent to @{ \@in }