$ perl -MData::Dump -e " my@f=1..3;my@g=4..6;push@f,\@g;push@g,@f;dd\@f,\@g; " do { my $a = [1, 2, 3, [4, 5, 6, 1, 2, 3, 'fix']]; $a->[3][6] = $a->[3]; ($a, $a->[3]); }