b   b   b   b   b   b     a   a   a   a   a   a   a     b   b   b   b   b   b
  b   b   b   b   b     a   a   a   a   a   a   a   a     b   b   b   b   b  
                      a   a   a   a   a   a   a   a   a                      
  c   c   c   c   c     a   a   a   a   a   a   a   a     c   c   c   c   c  
c   c   c   c   c   c     a   a   a   R   L   a   a     c   c   c   c   c   c
  c   c   c   c   c   c     a   a   RRRRR L a   a     c   c   c   c   c   c  
c   c   c   c   c   c   c     a   a  RRR  L   a     c   c   c   c   c   c   c
  c   c   c   c   c   c   c         RRRRRLLL      c   c   c   c   c   c   c  
c   c   c   c   c   c   c     d   d RRRRR L   d     c   c   c   c   c   c   c
  c   c   c   c   c   c     d   d   dRRRd   d   d     c   c   c   c   c   c  
c   c   c   c   c   c     d   d   d  RRR  d   d   d     c   c   c   c   c   c
  c   c   c   c   c     d   d   d   dRRRd   d   d   d     c   c   c   c   c  
                      d   d   d   d  RRR  d   d   d   d                      
  b   b   b   b   b     d   d   d   RRRRR   d   d   d     b   b   b   b   b  
b   b   b   b   b   b     d   d   d   d   d   d   d     b   b   b   b   b   b
  b   b   b   b   b   b     d   d   d   d   d   d     b   b   b   b   b   b  
b   b   b   b   b   b   b     d   d   d   d   d     b   b   b   b   b   b   b
  b   b   b   b   b   b   b                       b   b   b   b   b   b   b  
b   b   b   b   b   b   b     a   a   a   a   a     b   b   b   b   b   b   b
  b   b   b   b   b   b     a   a   a   a   a   a     b   b   b   b   b   b  
b   b   b   b   b   b     a   a   a   a   a   a   a     b   b   b   b   b   b
  b   b   b   b   b     a   a   a   a   a   a   a   a     b   b   b   b   b  
                      a   a   a   a   a   a   a   a   a                      
  c   c   c   c   c     a   a   a   a   a   a   a   a     c   c   c   c   c