my $y = { foo => "bar" };
my $X = { a => $y, b => $y, c => $y };

$Data::Dumper::Deepcopy = 1;

print Dumper($X);

##</code><code>##

$VAR1 = {
          'c' => {
                   'foo' => 'bar'
                 },
          'a' => {
                   'foo' => 'bar'
                 },
          'b' => {
                   'foo' => 'bar'
                 }
        };

##</code><code>##

$VAR1 = {
          'c' => {
                   'foo' => 'bar'
                 },
          'a' => $VAR1->{'c'},
          'b' => $VAR1->{'c'}
        };