.
                                      E
                       ­       s     s  c      s
                            c       p e         c
                          a          E             a
                         p         s    c           p
                         e        a      p          e
                         E        e       E         E
                          s         s     c          s
                            c        a  p         c
                               a       e         a
                                   p   •     p
                                        e