.
                                   M
                          a      a s       a
                        s         t u         s
                       t          r b           t
                      u         a    t          u
                      r         e     M         r
                      b         a     s          b
                       a         t     u         a
                        t          r   b         t
                          e         a          e
                               •     t       •
                                     e

.
                                     P
                             o     o r      o
                          r        n P         r
                         n       o    r         n
                         P       n    P         P
                         o        o   r          o
                          r        n P         r
                             n      or      n
                                  •   n    •

.
                                     F
                              i     i s      i
                           s       h F        s
                          h        is           h
                         F       h     F        F
                         i        i       s         i
                         s        h     F         s
                          h        i    s         h
                            F         h         F
                                i      •      i
               ­                        s
                                       h

.
                                  F
                          r­     r e       r
                       e        n c         e
                      n         ch           n
                      c       V      a         c
                      h       n      i         h
                       V       l      l         V
                        a         a           a
                          n       F        n
                             i      r       i    
                               la  e  all    
                                    n
              ­                      c
                                    h

.
                                   T
                            a    a r      a
                          r      t T         r
                         t      a     r        t
                        T      t       T      T
                        a       a     r       a
                         r        t   T       r
                           t        a         t
                               ●   r    ●
                                     t

.
                                   **
                              o   l e    l
                            l      **      e
                          e        l e        H
                         H       H  o        o
                         o       l      e        l
                         l        H    o        e
                          e       l     e        H
                           H       **        o
                              o      l         l
                                  l   e    e
                                      @

.
                                Friction
                          Friction Friction
                         Friction Friction F
                         Friction Friction Fr
                            Friction Frictio
                            riction Friction
                            Friction Frictio
                            riction Friction
                            Friction Frictio
                            riction Friction
                            Friction Frictio
                            riction Friction
                            Friction Frictio
                            riction Friction
                            Friction Frictio
                   Friction                 Friction
            Friction Friction   Friction Friction
           Friction Friction     Friction Friction
              Friction Fric           tion  Friction
                  Friction                    Friction