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An interesting BB

 
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Sat Apr 03, 2010 2:40 pm    Post subject: An interesting BB Reply with quote

Today's Brain Bashers' has an interesting pattern of clues. A VH, about.
Code:
Puzzle: BB040310sh
+-------+-------+-------+
| . . . | . . . | . . . |
| . . 9 | 4 . 5 | 8 . . |
| . 1 6 | 8 . 3 | 2 4 . |
+-------+-------+-------+
| . 4 7 | 3 . 2 | 5 9 . |
| . . . | . . . | . . . |
| . 6 1 | 9 . 7 | 4 3 . |
+-------+-------+-------+
| . 3 2 | 5 . 8 | 6 1 . |
| . . 4 | 2 . 6 | 3 . . |
| . . . | . . . | . . . |
+-------+-------+-------+
Keith
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Mogulmeister



Joined: 03 May 2007
Posts: 1151

PostPosted: Tue Apr 06, 2010 7:34 am    Post subject: Reply with quote

A nice puzzle - thanks Keith

Quote:
1)XY Wing <157> in blocks 1 & 4

2)Colouring on 7 eliminates 7 at r3c1 (eliminates a lot subsequently)

3)Colouring again on 7 again elminating 7 at r2c8 - if you prefer to see a structure it is a skyscraper on 7s r27c1 and r37c9
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Wed Apr 07, 2010 2:32 pm    Post subject: Reply with quote

First, a Type 3 UR58 in r19c23 forms subset 237 deleting 7 from r3c1. This results in the following code.

Code:
*--------------------------------------------------*
 | 4    278  38   | 167  126  19   | 179  5    136  |
 | 37   27   9    | 4    126  5    | 8    67   136  |
 | 5    1    6    | 8    79   3    | 2    4    79   |
 |----------------+----------------+----------------|
 | 8    4    7    | 3    16   2    | 5    9    16   |
 | 39   59   35   | 16   8    4    | 17   67   2    |
 | 2    6    1    | 9    5    7    | 4    3    8    |
 |----------------+----------------+----------------|
 | 79   3    2    | 5    4    8    | 6    1    79   |
 | 1    79   4    | 2    79   6    | 3    8    5    |
 | 6    58   58   | 17   3    19   | 79   2    4    |
 *--------------------------------------------------*

Then another funny xyz-wing 179 in r1c7
(1-9)r1c7 = r9c7 - r7c9 = (9-7)r7c1 = r2c1; r2c8<>7,
(7)r1c7; r2c8<>7,
(9)r1c7 - (9=7)r3c9; r2c8<>7 to complete the puzzle.

Ted
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Mogulmeister



Joined: 03 May 2007
Posts: 1151

PostPosted: Wed Apr 07, 2010 4:42 pm    Post subject: Reply with quote

(wrong thread - oops)
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Luke451



Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California

PostPosted: Wed Apr 07, 2010 6:34 pm    Post subject: Reply with quote

Ted, I've seen your "funny xyz-wing" called a "kraken cell," among other things.

Code:
 *--------------------------------------------------*
 | 4    278  38   | 167  126  19   | 179  5    136  |
 | 37   27   9    | 4    126  5    | 8    67   136  |
 | 5    1    6    | 8    79   3    | 2    4    79   |
 |----------------+----------------+----------------|
 | 8    4    7    | 3    16   2    | 5    9    16   |
 | 39   59   35   | 16   8    4    | 17   67   2    |
 | 2    6    1    | 9    5    7    | 4    3    8    |
 |----------------+----------------+----------------|
 | 79   3    2    | 5    4    8    | 6    1    79   |
 | 1    79   4    | 2    79   6    | 3    8    5    |
 | 6    58   58   | 17   3    19   | 79   2    4    |
 *--------------------------------------------------*

A less fearsome fish will also do it, though:
(7)r3c9=r7c9-r7c1=(7)r2c1 =>r2c8<>7
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Mogulmeister



Joined: 03 May 2007
Posts: 1151

PostPosted: Wed Apr 07, 2010 6:39 pm    Post subject: Reply with quote

What type of fish is a skyscraper ? Laughing
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Wed Apr 07, 2010 10:20 pm    Post subject: Reply with quote

Mogulmeister wrote:
What type of fish is a skyscraper ? Laughing

2x Sashimi X-Wings applied simultaneously.
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Luke451



Joined: 20 Apr 2008
Posts: 310
Location: Southern Northern California

PostPosted: Wed Apr 07, 2010 10:38 pm    Post subject: Reply with quote

Mogulmeister wrote:
What type of fish is a skyscraper ? Laughing

Well, calling it a skyscraper would have ruined my metaphor, and I never metaphor I didn't like Smile

Still, a swimming skyscraper is not as hilarious as one might imagine.

From this Sudopedia article:
Turbot Fish: "This pattern is also known as Skyscraper."
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daj95376



Joined: 23 Aug 2008
Posts: 3854

PostPosted: Wed Apr 07, 2010 11:07 pm    Post subject: Reply with quote

IMHO, the Sudopedia article that mentions Skyscraper under the definition of turbot fish is incorrect. Only one variation of the Skyscraper pattern fits as a turbot fish pattern. The general Skyscraper pattern would need four turbot fish to account for the four possible eliminations.

Similarly, the 4-cell Sashimi X-Wing pattern would need two turbot fish to account for the two possible eliminations. There is no mention in the Sudopedia article of a link between a turbot fish and a Sashimi X-Wing.

Thus, 2x 4-cell Sashimi X-Wing patterns can account for all four eliminatons in the general Skyscraper pattern.

Finally, one 4-cell single-digit chain can account for all four elimination in the general Skyscraper pattern. If I recall correctly, this is how Havard presented the general Skyscraper pattern. However, he did acknowledge its similarity to the turbot fish pattern. A similarity that many people have taken to mean equivalent.

Rambling and Regards, Danny
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tlanglet



Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills

PostPosted: Thu Apr 08, 2010 12:21 am    Post subject: Reply with quote

Luke451 wrote:
Ted, I've seen your "funny xyz-wing" called a "kraken cell," among other things.

Code:
 *--------------------------------------------------*
 | 4    278  38   | 167  126  19   | 179  5    136  |
 | 37   27   9    | 4    126  5    | 8    67   136  |
 | 5    1    6    | 8    79   3    | 2    4    79   |
 |----------------+----------------+----------------|
 | 8    4    7    | 3    16   2    | 5    9    16   |
 | 39   59   35   | 16   8    4    | 17   67   2    |
 | 2    6    1    | 9    5    7    | 4    3    8    |
 |----------------+----------------+----------------|
 | 79   3    2    | 5    4    8    | 6    1    79   |
 | 1    79   4    | 2    79   6    | 3    8    5    |
 | 6    58   58   | 17   3    19   | 79   2    4    |
 *--------------------------------------------------*

A less fearsome fish will also do it, though:
(7)r3c9=r7c9-r7c1=(7)r2c1 =>r2c8<>7


Maybe my understanding of a "Kraken" condition is not general since I have only see it applied as an additional constraint to single digit patterns such as x-wings, swordfish, etc. Could you explain how this xyz-wing pattern has a Kraken characteristic?

Also, I was looking for unusual patterns when I found the xyz-wing but a fishy skyscraper is truly unique.

Ted
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA

PostPosted: Thu Apr 08, 2010 12:50 am    Post subject: Reply with quote

Quote:
a fishy skyscraper is truly unique

Bring on the Sonoma juice!

Keith
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