f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  f  
1  6  1  2  2  3  5  5  8  9  6  2  3  4  7  7  7  7  8  8  8  8  1  1  1  1  1  1  1  1  1  1  
r  v  4  0  8  8  1  8  9  9  7  6  9  8  5  6  7  9  0  2  4  6  0  0  0  0  0  0  1  1  1  1  
      r  v  v  v  r  r  v  v  r  r  v  v  r  r  v  v  v  v  v  v  3  4  5  6  7  8  1  3  4  5  
                        1     1                                6  r  r  r  v  v  v  v  r  r  r