* * * * * *         where:  O C T O
               * *                   C T O
      -------------                  C T O B
       * * * * * *                     T O
     * * * * * *                       T O B E
    ---------------                    T O B E R
     O C T O B E R                       O B E R
                                           B E R
                                           B E
                                             E R
                                               R
                           are 11 prime numbers.