.

                                      E
                             d     d   i     d
                          i         b   l         i
                        b            e              b
                       l              E                l
                      e              d                 e
                      E              i                  E
                      d           b    l              d
                       i           e     E            i
                         b         d   i           b
                            l          b           l
                               e       l        e
                                        e