.

                                       B
                                a     ar     a
                             r       oq        r
                           o         u            o
                          q         e  B          q
                          u        a     r         u
                           B       o     q         B
                            r       u    e          r
                             o       B   a        o
                               k     r  o       k
                                  e     q     e
                                         u
                                         e