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And, I thought it was over ...

 
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Tue Jan 29, 2008 9:07 pm    Post subject: And, I thought it was over ... Reply with quote
I thought I had this one solved, then found another sticking place at the end.

Code:
Puzzle: M3937606sh(8)
+-------+-------+-------+
| 7 . . | . . 2 | . . 1 |
| . . 3 | . 7 8 | 2 . . |
| . 2 . | 1 6 9 | . 5 . |
+-------+-------+-------+
| . 1 . | . . . | 8 9 . |
| 2 . . | . . . | . . 3 |
| . 4 5 | . . . | . 7 . |
+-------+-------+-------+
| . 8 . | 7 3 4 | . 2 . |
| . . 2 | . 8 6 | 7 . . |
| 4 . . | . . 1 | . . 8 |
+-------+-------+-------+


Highly recommended!

Keith
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Tue Jan 29, 2008 9:35 pm    Post subject: Reply with quote
Looking anew at that sticking place: I suppose I'm just not a city boy! (But I am unique.)

Keith
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
PostPosted: Tue Jan 29, 2008 9:52 pm    Post subject: Reply with quote
Skyscraper (9),
Quote:
I thought I had this one solved,

but ... this position
Code:
+--------------------------+--------------------------+--------------------------+
| 7       69      69       | 3       5       2        | 4       8       1        |
| 1       5       3        | 4       7       8        | 2       6       9        |
| 8       2       4        | 1       6       9        | 3       5       7        |
+--------------------------+--------------------------+--------------------------+
| 3       1       67       | 2       4       57       | 8       9       56       |
| 2       79      8        | 6       19      57       | 15      4       3        |
| 69      4       5        | 8       19      3        | 16      7       2        |
+--------------------------+--------------------------+--------------------------+
| 569     8       1        | 7       3       4        | 569     2       56       |
| 59      3       2        | 59      8       6        | 7       1       4        |
| 4       679     679      | 59      2       1        | 569     3       8        |
+--------------------------+--------------------------+--------------------------+

needs another coloring scheme (removes 6 from r4c3, r6c7, r7c1, r7c9) to solve.

Guess I AM a city boy Twisted Evil
but nothing unique with that (the 7 in row 9 spoils the fun regardless)

___

talking about city/non-city boys: http://www.youtube.com/watch?v=QorkFwpOo6E
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Tue Jan 29, 2008 10:22 pm    Post subject: Reply with quote
nataraj wrote:
Skyscraper (9),
Quote:
I thought I had this one solved,

but ... this position
Code:
+--------------------------+--------------------------+--------------------------+
| 7       69      69       | 3       5       2        | 4       8       1        |
| 1       5       3        | 4       7       8        | 2       6       9        |
| 8       2       4        | 1       6       9        | 3       5       7        |
+--------------------------+--------------------------+--------------------------+
| 3       1       67       | 2       4       57       | 8       9       56       |
| 2       79      8        | 6       19      57       | 15      4       3        |
| 69      4       5        | 8       19      3        | 16      7       2        |
+--------------------------+--------------------------+--------------------------+
| 569     8       1        | 7       3       4        | 569     2       56       |
| 59      3       2        | 59      8       6        | 7       1       4        |
| 4       679     679      | 59      2       1        | 569     3       8        |
+--------------------------+--------------------------+--------------------------+

needs another coloring scheme (removes 6 from r4c3, r6c7, r7c1, r7c9) to solve.

Guess I AM a city boy Twisted Evil
but nothing unique with that (the 7 in row 9 spoils the fun regardless)

___

talking about city/non-city boys: http://www.youtube.com/watch?v=QorkFwpOo6E


I must be VERY NOT a city boy. If you see the XY-wing that takes out <6> in R1C3, (which does not matter hereafter) you reach the position I did, but I had used no skyscrapers. I did use a hard-to-spot W-wing, plus two XY-wings, one of which I mention above.

Then, there are three columns (two skyscrapers) that take out <6> in R79C7, solving the puzzle.

But, in Nataraj' grid above is the unique swordfish: <59> in C147. To avoid the DP, R7C9 cannot be <6>.

Keith Exclamation
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
PostPosted: Tue Jan 29, 2008 10:40 pm    Post subject: Reply with quote
keith wrote:

But, in Nataraj' grid above is the unique swordfish: <59> in C147. To avoid the DP, R7C9 cannot be <6>.


That's interesting! Could you please elaborate, Keith? I have the feeling I am about to learn an important lesson. More specifically, unique swordfish? I assume you refer to the pattern of {59} in r78c1, r89c4 and r79c7, but how can removing the extra 6 spoil the deadly pattern? Pls forgive me for being tense - as you must have realized by now, uniqueness arguments are among my many weak points.
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keith



Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
PostPosted: Tue Jan 29, 2008 11:22 pm    Post subject: Reply with quote
Nataraj,

Here is my position:

Code:
+-------------+-------------+-------------+
| 7   6   9   | 3   5   2   | 4   8   1   |
| 1   5   3   | 4   7   8   | 2   6   9   |
| 8   2   4   | 1   6   9   | 3   5   7   |
+-------------+-------------+-------------+
| 3   1   67  | 2   4   57  | 8   9   56  |
| 2   79  8   | 6   19  57  | 15  4   3   |
| 69  4   5   | 8   19  3   | 16  7   2   |
+-------------+-------------+-------------+
|#569 8   1   | 7   3   4   |#569 2   56  |
|#59  3   2   |#59  8   6   | 7   1   4   |
| 4   79  67  |#59  2   1   |#569 3   8   |
+-------------+-------------+-------------+

The cells # are a "unique swordfish" in that that they are laid out like a swordfish, and <59> in each is a deadly pattern (DP).

To avoid the DP, one of R7C1, R7C7, and R9C7 must be <6>. They all have a common peer (shared buddy): R7C9 cannot be <6>.

(My first explanation was deliberately vague, not to spoil the fun for others.)

And, by the way, I was really surprised to get stuck when I thought the puzzle was solved, and presumed only singles remained.

Keith
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Marty R.



Joined: 12 Feb 2006
Posts: 5770
Location: Rochester, NY, USA
PostPosted: Wed Jan 30, 2008 12:15 am    Post subject: Reply with quote
One W-Wing, an XY-Wing and two ERs. In the above grid the ERI on 6 is in r6c3 and it takes out the 6 from r6c7.

Very nice work on that unique swordfish. Idea
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nataraj



Joined: 03 Aug 2007
Posts: 1048
Location: near Vienna, Austria
PostPosted: Wed Jan 30, 2008 7:10 am    Post subject: Reply with quote
Thanks, keith ! I see it clearly now how that works. Maybe next time I'll be able to figure it out myself.


nataraj wrote:
but how can removing the extra 6 spoil the deadly pattern?

Somehow my brain made me look at the 6 in r7c6 all the time instead of r7c9. Couldn't figure out how you could remove that. Should have read your post properly. Well, it was close to midnight ...
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storm_norm



Joined: 18 Oct 2007
Posts: 1741
PostPosted: Wed Jan 30, 2008 10:16 am    Post subject: Reply with quote
keith,

that is pretty sweet.
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