.
                                         T
                                B     BP      B
                              P       TB         P
                             T          P            T
                            B        T    B          B
                            P        P     T         P
                             T        B    P        T
                               B        T B        B
                                  P       P       P

                                         TBP

.
                                          I
                   ­              R     RL     R
                               L        IR        L
                              I           I.           I
                              R      I     R        R
                              L       L    I         L
                               I        R  L         I
                                R        I          R
                                   l       R       I
                                      R   L   R
                                            ~
                 ­                           L

.
                   Concrete
              Concrete  Conc
             Concrete Concre
              Concrete Concr
                Concrete Co
                ncrete Concr
                ete Concrete
                ncrete Concr
                 ete Concrete
                 Concrete Co
          Concrete      Concrete
      Concrete Con  cret e Concre
     teConcreteCon crete Concrete
       Concrete Con   crete Concre
            Concrete        Concrete

.                                    
                                      
                                     A
                        A           L            A
                               L     L      L
                     A        l     W      A    Y    S
                                A    A     A
                           Y         Y           Y
                        S             S               S

.

                                      W
                                a    a l     a
                              l       l f        l
                             l         l           l
                             f      o    w      f
                              l      e    r       l
                               o     Wa      o
                                 w    ll     w
                                    e        e
                                         r

.
                                   M
                             o   o u    o
                           u     n d      u
                          n        s          n
        ­                 d       M o        d
                          s      u     n       s
                          M    d      s     M
                            o     M  o      o
                              u      u      u
       ­                           n       n
                                       d

.      
                                     D
                              i     i a       i
                            a      mo        a
                ­          m       n d        m
                          o          s             o
                          n       D    i          n
                          d       a    m         d
                           s       o    n          s
                            D      d   s         D
                               i       D         i
                                  a    ~     a
                                        ~