

 NNTBs dark marking
NNTBs dark marking
       NNTBs white marking
NNTBs white marking
       NNTB dark marking
NNTB dark marking
       marking in adjacent region
marking in adjacent region
  center
center
       p. end
p. end
       f. end
f. end
 
 NNTBs dark marking
NNTBs dark marking
       NNTBs white marking
NNTBs white marking
       NNTB dark marking
NNTB dark marking
       marking in adjacent region
marking in adjacent region
  center
center
       p. end
p. end
       f. end
f. end