.
                                    H
                            a     a p      a
                          p       p y        p
                         p        H a         p
                         y          p            y
                        H        p   y         H
                         a        H   a         a
                          p       p    p        p
                           p       y H        p
                              y      a        y
                                      P
                                      p
                                      y