Page 14 of 33

Re: Prokovich game

Posted: Sun Sep 05, 2010 11:11 am
by Dusk Eagle
I would not assume that a move by a professional is a mistake unless other pros say it is.

Re: Prokovich game

Posted: Sun Sep 05, 2010 3:33 pm
by Joaz Banbeck
@Dfan: Can you delay a day or so before posting the next move? Some people are away for labor day, and some of us will have to completely re-assess the position after the tenuki.

Re: Prokovich game

Posted: Sun Sep 05, 2010 8:28 pm
by dfan
Sure thing. I too wanted to give people a chance to react to this move.

Re: Prokovich game

Posted: Tue Sep 07, 2010 10:45 am
by dfan
Time's up!

Click Here To Show Diagram Code
[go]$$Wcm38 ACTUAL GAME: Move 38
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . . O X . . X . . . . O X . . |
$$ | . . . O . X . O X . . O X . . O . . . |
$$ | . . O X X . . O . X . O . X . . O . . |
$$ | . . O . . . . . 1 O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: Prokovich game

Posted: Tue Sep 07, 2010 11:38 am
by emeraldemon
Click Here To Show Diagram Code
[go]$$Bcm39 a guess
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . 2 X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . 4 O X . . X . . . . O X . . |
$$ | . . . O . X 3 O X . . O X . . O . . . |
$$ | . . O X X . . O . X 1 O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


White 42 looks pretty dangerous.

Re: Prokovich game

Posted: Tue Sep 07, 2010 11:42 am
by Kirby
Dusk Eagle wrote:I would not assume that a move by a professional is a mistake unless other pros say it is.


Well, somebody has to lose the game :)

Though, I admit that professional mistakes are probably much more infrequent and slight than ours.

Re: Prokovich game

Posted: Tue Sep 07, 2010 3:01 pm
by Dusk Eagle
Obviously professionals make mistakes in most if not all of their games, but the vast majority of us are far too weak to identify which moves are actual mistakes. Thus, I always try to withhold negative judgment until another pro says a certain move was wrong.

Re: Prokovich game

Posted: Tue Sep 07, 2010 4:48 pm
by dfan
Click Here To Show Diagram Code
[go]$$Bcm39 ACTUAL GAME: Move 39
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . . O X . . X . . . . O X . . |
$$ | . . . O . X . O X . . O X . . O . . . |
$$ | . . O X X . . O . X 1 O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: Prokovich game

Posted: Tue Sep 07, 2010 5:15 pm
by Joaz Banbeck
emeraldemon wrote:
Click Here To Show Diagram Code
[go]$$Bcm39 a guess
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . 2 X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . 4 O X . . X . . . . O X . . |
$$ | . . . O . X 3 O X . . O X . . O . . . |
$$ | . . O X X . . O . X 1 O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


White 42 looks pretty dangerous.


:b39: is forced, of course. But :w40: is the wrong direction.

Click Here To Show Diagram Code
[go]$$Bcm39 a guess
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . 2 X . . . . . . . . . . . . . . . |
$$ | . . a b . . . . . . . . . . . . O . . |
$$ | . . . c . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . . O X . . X . . . . O X . . |
$$ | . . . O . X . O X . . O X . . O . . . |
$$ | . . O X X . . O . X 1 O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


I don't have the tactical skills to know exactly what would be best for black ( a? b? c? ) but black would love to cut off :w40: and :w42: while invading/flattening white's territory, while still having access to the center. If white wants to contest :b38:, he has to try to cut it off with D10.

Re: Prokovich game

Posted: Tue Sep 07, 2010 5:17 pm
by mitsun
emeraldemon wrote:
Click Here To Show Diagram Code
[go]$$Bcm39
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . 2 X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . 4 O X . . X . . . . O X . . |
$$ | . . . O . X 3 O X . . O X . . O . . . |
$$ | . . O X X . . O . X 1 O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

White 42 looks pretty dangerous.

B can win the inside capturing race with the placement shown below:
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . O O X . . X . . . . O X . . |
$$ | . . . O . X X O X . . O X . . O . . . |
$$ | . . O X X . . O . X X O . X . . O . . |
$$ | . . O . . . 1 . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

The question then is whether W can cut and capture something on the outside. Here is a likely attempt.
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . 5 . . . . X . X X O . . |
$$ | . . . O . O O X 4 . X . . . . O X . . |
$$ | . . . O . X X O X 6 8 O X . . O . . . |
$$ | . . O X X . 3 O 7 X X O . X . . O . . |
$$ | . . O . . . 1 2 O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Looking a little deeper, B can still win with the following continuation. Note that B3 cannot be used to capture W2 in a ladder, so B has to play underneath. In the end, B wins as long as the ladder starting with W4 does not work. So the B "tenuki" really was a ladder breaker, as we suspected.
Click Here To Show Diagram Code
[go]$$B
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . . X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . 4 . . . . . . . O . . . |
$$ | . . . . . . . X 2 . . . X . X X O . . |
$$ | . . . O . O O X O 1 X . . . . O X . . |
$$ | . . . O . X X O X O O O X . . O . . . |
$$ | . . O X X . X O X X X O . X . . O . . |
$$ | . . O . . . X O O O X 3 . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

So I guess a trade is coming:
Click Here To Show Diagram Code
[go]$$Bcm39
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . 3 X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . 2 O X . . X . . . . O X . . |
$$ | . . . O . X . O X . . O X . . O . . . |
$$ | . . O X X . . O . X 1 O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: Prokovich game

Posted: Tue Sep 07, 2010 6:36 pm
by Joaz Banbeck
@Mitsun: An impressive piece of analysis.
Image

Re: Prokovich game

Posted: Wed Sep 08, 2010 7:49 am
by dfan
As mitsun predicted.

Click Here To Show Diagram Code
[go]$$Wcm40 ACTUAL GAME: Moves 40-41
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O , . . . . . , . . . . . , . . . |
$$ | . . 2 X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . 1 O X . . X . . . . O X . . |
$$ | . . . O . X . O X . . O X . . O . . . |
$$ | . . O X X . . O . X X O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]

Re: Prokovich game

Posted: Wed Sep 08, 2010 9:07 am
by Joaz Banbeck
This would be horrible for white:

Click Here To Show Diagram Code
[go]$$Wcm40
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . b . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . a O 4 . . . . . , . . . . . , . . . |
$$ | . . 2 X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . 1 O X . . X . . . . O X . . |
$$ | . . . O . X . O X . . O X . . O . . . |
$$ | . . O X X . . O . X X O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


even if :w42: were at 'a' or 'b' or elsewhere nearby.


Running with :w42: looks suicidal, even if there were ko theats in the opening. Now a move around 'a' is a ladder breaker for black:

Click Here To Show Diagram Code
[go]$$Wcm40
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . a . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . 7 . . . . . . . . . . . . . . . . |
$$ | . . 6 5 3 . . . . . . . . . . . O . . |
$$ | . 8 O 4 . . . . . , . . . . . , . . . |
$$ | . . 2 X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . 1 O X . . X . . . . O X . . |
$$ | . . . O . X . O X . . O X . . O . . . |
$$ | . . O X X . . O . X X O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]



So white has little choice but to walk into the hane at the head of two stones:

Click Here To Show Diagram Code
[go]$$Wcm40
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O 3 4 . . . . , . . . . . , . . . |
$$ | . . 2 X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . 1 O X . . X . . . . O X . . |
$$ | . . . O . X . O X . . O X . . O . . . |
$$ | . . O X X . . O . X X O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


It is not pleasant for white to fight like this, but all other options involve delaying the fight and getting closer to the power of the black shimari up top.

Re: Prokovich game

Posted: Wed Sep 08, 2010 1:12 pm
by mitsun
Joaz Banbeck wrote:@Mitsun: An impressive piece of analysis.
Thanks. However, a professional would have to analyze a lot more than that before making a move. For example, why can't B atari at J7 to break the ladder? And why can't W give up the cutting stone to connect under by switching to M2 atari? (Maybe B has to play M2 before K5, although W can still connect under.) Of course it helps a kibitzer to know that D9 must have been a ladder breaker :)

Re: Prokovich game

Posted: Wed Sep 08, 2010 1:25 pm
by topazg
Joaz Banbeck wrote:So white has little chice but to walk into the hane at the head of two stones:

Click Here To Show Diagram Code
[go]$$Wcm40
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O 3 4 . . . . , . . . . . , . . . |
$$ | . . 2 X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . 1 O X . . X . . . . O X . . |
$$ | . . . O . X . O X . . O X . . O . . . |
$$ | . . O X X . . O . X X O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]


It is not pleasant for white to fight like this, but all other options involve delaying the fight and getting closer to the power of the black shimari up top.


Hmmm, I don't believe this for a second. I've never seen a pro play like this, particularly with those stones in the top left. Perhaps a contact in the top left?:

Click Here To Show Diagram Code
[go]$$Wcm40
$$ ---------------------------------------
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . X . . . . |
$$ | . . X , X . . . . , . . . . . , X . . |
$$ | . . 3 4 . . . . . . . . . . . . . . . |
$$ | . . 5 6 . . . . . . . . . . . . . . . |
$$ | . . 7 . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . O . . . . . . , . . . . . , . . . |
$$ | . . 2 X . . . . . . . . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . O . . |
$$ | . . . . . . . . . . . . . . . O . . . |
$$ | . . . . . . . . . . . . X . X X O . . |
$$ | . . . O . 1 O X . . X . . . . O X . . |
$$ | . . . O . X . O X . . O X . . O . . . |
$$ | . . O X X . . O . X X O . X . . O . . |
$$ | . . O . . . . . O O X . . . . . . . . |
$$ | . . . . . . . . . . . . . . . . . . . |
$$ ---------------------------------------[/go]