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		| arkietech 
 
 
 Joined: 31 Jul 2008
 Posts: 1834
 Location: Northwest Arkansas USA
 
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				|  Posted: Mon May 21, 2012 6:48 am    Post subject: Collection 5/21/12 |   |  
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				|  	  | Code: |  	  | *-----------*
 |.7.|.8.|4..|
 |.4.|7.2|...|
 |2.5|.3.|..7|
 |---+---+---|
 |..8|...|.1.|
 |..6|.5.|7.8|
 |79.|...|.3.|
 |---+---+---|
 |9..|.65|8..|
 |...|8..|.79|
 |..1|2..|3..|
 *-----------*
 
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		| tlanglet 
 
 
 Joined: 17 Oct 2007
 Posts: 2468
 Location: Northern California Foothills
 
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				|  Posted: Mon May 21, 2012 12:44 pm    Post subject: |   |  
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				| Code after basics: 
  	  | Code: |  	  | *--------------------------------------------------------------------* | 16     7      39     | 5      8      169    | 4      269    1236   |
 | 168    4      39     | 7      19     2      | 1569   5689   1356   |
 | 2      168    5      | 1469   3      1469   | 169    689    7      |
 |----------------------+----------------------+----------------------|
 | 345    235    8      | 3469   2479   34679  | 269    1      246    |
 | 134    123    6      | 349    5      349    | 7      249    8      |
 | 7      9      24     | 146    124    8      | 256    3      2456   |
 |----------------------+----------------------+----------------------|
 | 9      23     7      | 134    6      5      | 8      24     124    |
 | 3456   2356   24     | 8      14     134    | 1256   7      9      |
 | 4568   568    1      | 2      79     79     | 3      456    456    |
 *--------------------------------------------------------------------*
 
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 axy-wing(24-3)r8c3+r7c2/r8c6=(1)r8c6-(1=4=2)r8c53-(2=3)r7c2; r7c4,r8c12<>3
 
 Ted
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		| arkietech 
 
 
 Joined: 31 Jul 2008
 Posts: 1834
 Location: Northwest Arkansas USA
 
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				|  Posted: Mon May 21, 2012 1:09 pm    Post subject: |   |  
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				|  	  | tlanglet wrote: |  	  | axy-wing(24-3)r8c3+r7c2/r8c6=(1)r8c6-(1=4=2)r8c53-(2=3)r7c2; r7c4,r8c12<>3
 | 
 Nice find Ted.
   
 also there is a nice w-wing hiding.
 
 
  	  | Code: |  	  | *--------------------------------------------------------------------* | 16     7      39     | 5      8      169    | 4      269    1236   |
 | 168    4      39     | 7      19     2      | 1569   5689   1356   |
 | 2      168    5      | 1469   3      1469   | 169    689    7      |
 |----------------------+----------------------+----------------------|
 | 345    235    8      | 3469   2479   34679  | 269    1      246    |
 | 134    123    6      | 349    5      349    | 7      249    8      |
 | 7      9      24     | 146    124    8      | 256    3      2456   |
 |----------------------+----------------------+----------------------|
 | 9      3-2    7      |#134    6      5      | 8     *24     124    |
 | 3456   2356  *24     | 8     #14    #134    | 156-2  7      9      |
 | 4568   568    1      | 2      79     79     | 3      456    456    |
 *--------------------------------------------------------------------*
 w-wing
 (2=4)r7c8-r7c4=r8c56-(4=2)r8c3 => r7c2,r8c7<>2
 
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		| tlanglet 
 
 
 Joined: 17 Oct 2007
 Posts: 2468
 Location: Northern California Foothills
 
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				|  Posted: Mon May 21, 2012 1:30 pm    Post subject: |   |  
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				| A second "similar" w-wing also exits but it needs a pincer transport. 
 (4=2)r7c3-r5c2=r5c8-(2=4)r7c8-r9c89=r9c1; r45c1,r8c3<>4
 
 I normally approach a puzzle in a given sequence of steps and simply use the first solution that I find. In this case, I never got around to looking for w-wings since I was looking for xy-wings first, including almost xy-wings. That is also why I recently missed two xyz-wing solutions since I never check for them early in my sequence.
 
 Ted
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		| arkietech 
 
 
 Joined: 31 Jul 2008
 Posts: 1834
 Location: Northwest Arkansas USA
 
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				|  Posted: Mon May 21, 2012 1:53 pm    Post subject: |   |  
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				| I wonder if anyone has studied whether xy-wings or w-wings solve the most puzzles. To me a w-wing is much easier to spot (this one being an exception). |  | 
	
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		| keith 
 
 
 Joined: 19 Sep 2005
 Posts: 3355
 Location: near Detroit, Michigan, USA
 
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				|  Posted: Mon May 21, 2012 4:37 pm    Post subject: |   |  
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				|  	  | arkietech wrote: |  	  | I wonder if anyone has studied whether xy-wings or w-wings solve the most puzzles. To me a w-wing is much easier to spot (this one being an exception). | 
 I think that is an unknowable question (or answer?).  The reason is that puzzles are screened based on the techniques needed to solve them.  I imagine that some sites sort puzzles so that, at some level, XY-wings will not solve them.  I doubt they screen for W- or M-wings.
 
 Keith
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		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
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				|  Posted: Mon May 21, 2012 4:45 pm    Post subject: |   |  
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				|  	  | Quote: |  	  | w-wing (2=4)r7c8-r7c4=r8c56-(4=2)r8c3 => r7c2,r8c7<>2
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 Dan, it looks like you're saying that the W-Wing solves the puzzle. I missed that because after the W-Wing I needed the X-Wing on 2 in r17.
 
 This is where the W-Wing takes me:
  	  | Code: |  	  | +-------------+----------------+----------------+
 | 16   7   39 | 5    8    169  | 4    269  1236 |
 | 168  4   39 | 7    19   2    | 1569 5689 1356 |
 | 2    168 5  | 1469 3    1469 | 169  689  7    |
 +-------------+----------------+----------------+
 | 345  25  8  | 3469 2479 4679 | 269  1    246  |
 | 134  12  6  | 349  5    49   | 7    249  8    |
 | 7    9   24 | 146  124  8    | 256  3    2456 |
 +-------------+----------------+----------------+
 | 9    3   7  | 14   6    5    | 8    24   124  |
 | 456  256 24 | 8    14   3    | 156  7    9    |
 | 4568 568 1  | 2    79   79   | 3    456  456  |
 +-------------+----------------+----------------+
 
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 Play this puzzle online at the Daily Sudoku site
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		| arkietech 
 
 
 Joined: 31 Jul 2008
 Posts: 1834
 Location: Northwest Arkansas USA
 
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				|  Posted: Mon May 21, 2012 5:04 pm    Post subject: |   |  
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				|  	  | Marty R wrote: |  	  | Dan, it looks like you're saying that the W-Wing solves the puzzle. I missed that because after the W-Wing I needed the X-Wing on 2 in r17. 
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 Check the 1's in col 6.
 
 I should have indicated lclste.
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		| Clement 
 
 
 Joined: 24 Apr 2006
 Posts: 1113
 Location: Dar es Salaam Tanzania
 
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				|  Posted: Mon May 21, 2012 6:25 pm    Post subject: Collection 5/21/12 |   |  
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				| We can eliminate 3 in r7c4 using the numbers left in r7c8 the 2 and 4 (Digit Forcing Chains) as follows:- If r7c8=2 => r7c2=3; r7c4<>3.
 If r7c8=4 => r9c89<>4, r8c3=2 => r7c2=3; r7c4<>3 solves it.
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		| Marty R. 
 
 
 Joined: 12 Feb 2006
 Posts: 5770
 Location: Rochester, NY, USA
 
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				|  Posted: Mon May 21, 2012 7:20 pm    Post subject: |   |  
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				|  	  | Quote: |  	  | Check the 1's in col 6. | 
 
 Up to my old tricks.
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