.
                                           T
                                  P     h  e     P
                               e        P  e         e
                             r             r             r
                            f              f                f
 ­                           e            e  c              e
     ­                       c            t    S             c
                            t             t   o             t
                             S            r m           S
                               t            T             t
                                o          h           o
                                   r        e         r
                                     m           m