.
                                        C
                                 a     as      a
                               s       ba         s
                             b         h            b
                           a         c    a           a
                           h         s     b           h
                           c         a      h          c
                            a         c    a           a
                             s         s   b           s
                              b          a           b
                                 a       h        a
                                    h    ●     h