EVENT
BOARDSIZE 19
SETUP W K17 M18 N17 O17 M16 
SETUP B D16 H17 L18 N18 M17 Q16 Q14 
MARK 1@N18 3@L18 2@N17 4@M16 @@O18
COM
Reference Diagram to Problem 16. Black to play.  

White 4 instead of @ is the usual variation.  

ENDCOM
B 1 L17
USER
CORERECT ANSWER
ENDUSER
COM
Correct Answer.
ENDCOM
W 2 L16
B 3 K18
W 4 O18
COM
After White 4 and ...  
ENDCOM
B 5 Q18
MARK A@O15
COM
... Black 5 are exchanged, White must think about completing
her shape with a move at A.  <= 
ENDCOM