my $a = [qw{v1 v2}];
my %h = (
         k1 => {
             k11 => $a,
             k12 => 'w00t!',
         },
         k2 => {
             k21 => 'what?',
             k22 => $a,
         },
        );

use Data::Dumper;
#print Dumper(\%h);

my $h2; $h2 = {
          'k2' => {
                    'k21' => 'what?',
                    'k22' => [
                               'v1',
                               'v2'
                             ]
                  },
          'k1' => {
                    'k11' => $h2->{'k2'}{'k22'},
                    'k12' => 'w00t!'
                  }
};

print Dumper($h2);