use Data::Dumper;
$Data::Dumper::Purity=1;
use strict;
my $array=[0,1];
$array->[0]=\$array->[1];
$array->[1]=\$array->[0];
print Dumper($array);

##</code><code>##

$VAR1 = [
          \\do{my $o},
          do{my $o}
        ];
${${$VAR1->[0]}} = $VAR1->[0];
$VAR1->[1] = ${$VAR1->[0]};