my $reference = [              
 [ 7, 8, 9 ],
 [ 10, 11, 12 ],
];
print Dumper $reference;
print Dumper \$reference;
$VAR1 = [ 
          [ 
            7,
            8,
            9
          ],
          [ 
            10,
            11,
            12
          ]
        ];
$VAR1 = \[  
            [ 
              7,
              8,
              9
            ],
            [ 
              10,
              11,
              12
            ]
          ];