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Jan 25 VH
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keith



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

PostPosted: Mon Feb 08, 2010 3:31 am    Post subject: Reply with quote

In the words of the Susser:
Code:
+-------------------+-------------------+-------------------+
| 7     2     38    | 5     9     368   | 4     36    1     |
| 13    6     9     | 134   34    7     | 8     5     2     |
| 5     48    1348  | 2     38    1368  | 7     36    9     |
+-------------------+-------------------+-------------------+
| 48    3     4568  | 7     1     489   | 69    2     58    |
| 9     7     68    | 38    5     2     | 36    1     4     |
| 2     1     458   | 3489  6     3489  | 39    7     58    |
+-------------------+-------------------+-------------------+
| 6     489   13    | 13489 348   5     | 2     49    7     |
| 48    5     2     | 6     7     489   | 1     49    3     |
| 13    49    7     | 1349  2     1349  | 5     8     6     |
+-------------------+-------------------+-------------------+

Squares R1C3 and R1C6 in row 1, R4C1, R4C3, R4C6 and R4C9 in row 4, R5C3 and R5C4 in row 5, R6C3, R6C4, R6C6 and R6C9 in row 6 and R8C1 and R8C6 in row 8 form a Squirmbag pattern on possibility <8>. All other instances of this possibility in columns 1, 3, 4, 6 and 9 can be removed.

R3C3 - can remove <8> from <1348> leaving <134>.
R3C6 - can remove <8> from <1368> leaving <136>.
R7C4 - can remove <8> from <13489> leaving <1349>.
Code:
+----------------+----------------+----------------+
| 7    2    38   | 5    9    368  | 4    36   1    |
| 13   6    9    | 134  34   7    | 8    5    2    |
| 5    48   134  | 2    38   136  | 7    36   9    |
+----------------+----------------+----------------+
| 48   3    4568 | 7    1    49   | 69   2    58   |
| 9    7    68   | 38   5    2    | 36   1    4    |
| 2    1    458  | 3489 6    349  | 39   7    58   |
+----------------+----------------+----------------+
| 6    489  13   | 1349 348  5    | 2    49   7    |
| 48   5    2    | 6    7    489  | 1    49   3    |
| 13   49   7    | 1349 2    1349 | 5    8    6    |
+----------------+----------------+----------------+

Squares R6C6 (XYZ), R6C7 (XZ) and R4C6 (YZ) form an XYZ-Wing pattern on <9>. All squares that are buddies of all three squares cannot be <9>.

R6C4 - can remove <9> from <3489> leaving <348>.
Code:
+----------------+----------------+----------------+
| 7    2    38   | 5    9    368  | 4    36   1    |
| 13   6    9    | 13   4    7    | 8    5    2    |
| 5    48   134  | 2    38   136  | 7    36   9    |
+----------------+----------------+----------------+
| 48   3    4568 | 7    1    49   | 69   2    58   |
| 9    7    68   | 38   5    2    | 36   1    4    |
| 2    1    458  | 348  6    349  | 39   7    58   |
+----------------+----------------+----------------+
| 6    89   13   | 139  38   5    | 2    4    7    |
| 48   5    2    | 6    7    48   | 1    9    3    |
| 13   49   7    | 1349 2    134  | 5    8    6    |
+----------------+----------------+----------------+

Squares R3C6 (XYZ), R3C8 (XZ) and R2C4 (YZ) form an XYZ-Wing pattern on <3>. All squares that are buddies of all three squares cannot be <3>.

R3C5 - can remove <3> from <38> leaving <8>.

Done.

Keith
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kragzy



Joined: 01 May 2007
Posts: 112
Location: Australia

PostPosted: Mon Feb 08, 2010 6:12 am    Post subject: Reply with quote

A Squirmbag!! Now why on earth didn't I see that?

After three happy years of picking wings in a flash and recently adding skyscrapers to my box of tricks, now I discover there's such a thing as a squirmbag! Good grief. Rolling Eyes

Thanks for your reply Keith. Squirmbags look like a whole lot of fun, but I'm only a mere mortal - think I'll leave 'em for another day!!

And I think my contention stands that this is the first DailySudoku puzzle that was unsolvable with just the standard wings.

Very Happy Very Happy
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keith



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

PostPosted: Mon Feb 08, 2010 7:25 am    Post subject: Reply with quote

Oops!

Here is what I should have pasted from the Susser:
Quote:
Squares R3C2 and R7C2 in column 2 and R3C5 and R7C5 in column 5 form a Simple X-Wing pattern on possibility <8>. All other instances of this possibility in rows 3 and 7 can be removed.

R3C3 - can remove <8> from <1348> leaving <134>.
R7C4 - can remove <8> from <13489> leaving <1349>.
R3C6 - can remove <8> from <1368> leaving <136>.

The "squirmbag" is the complement of this X-wing.

You probably don't want to know this, but any N-fish in the rows (columns) has a complementary 9(or lesser)-N fish in the columns (rows) that makes the same eliminations.

An X-wing is a 2-fish, a swordfish is a 3-fish, a jellyfish is a 4-fish, etc.

Keith.
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dulaby



Joined: 02 May 2007
Posts: 13

PostPosted: Mon Feb 08, 2010 5:21 pm    Post subject: january 25VH Reply with quote

SORRY AGAIN KRAGZY, THE XYZ ON BOXES 5 AND 6 IS:

349 ,39 AND 49
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kragzy



Joined: 01 May 2007
Posts: 112
Location: Australia

PostPosted: Mon Feb 08, 2010 10:13 pm    Post subject: Reply with quote

I hate to harp on this - must be getting very boring for everyone.

But...

The reason I didn't see the XYZ on 349 in Box 5 is because I was unable, using normal VH techniques, to remove the 8 from R6C6. Keith's squirmbag deleted it but not its (apparently) complementary X wing - see Keith's last post.

Anyway, perhaps that is enough for now. Think I'll do a couple of EASYs to relax!!

Cheers
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keith



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

PostPosted: Mon Feb 08, 2010 11:15 pm    Post subject: Reply with quote

kragzy wrote:
I hate to harp on this - must be getting very boring for everyone.

But...

The reason I didn't see the XYZ on 349 in Box 5 is because I was unable, using normal VH techniques, to remove the 8 from R6C6. Keith's squirmbag deleted it but not its (apparently) complementary X wing - see Keith's last post.

Anyway, perhaps that is enough for now. Think I'll do a couple of EASYs to relax!!

Cheers

Not exactly. The X-wing and the squirmbag take out 8 in the same three cells.

After that,
Code:
+----------------+----------------+----------------+
| 7    2    38   | 5    9    368  | 4    36   1    |
| 13   6    9    | 134  34   7    | 8    5    2    |
| 5    48   134  | 2    38   136  | 7    36   9    |
+----------------+----------------+----------------+
| 48   3    4568 | 7    1    489  | 69   2    58   |
| 9    7    68   | 38   5    2    | 36   1    4    |
| 2    1    458  | 3489 6    3489 | 39   7    58   |
+----------------+----------------+----------------+
| 6    489  13   | 1349 348  5    | 2    49   7    |
| 48   5    2    | 6    7    489  | 1    49   3    |
| 13   49   7    | 1349 2    1349 | 5    8    6    |
+----------------+----------------+----------------+

you can eliminate 8 in R46C6 because the 8 in B5 must be in C4.

Keith
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kragzy



Joined: 01 May 2007
Posts: 112
Location: Australia

PostPosted: Mon Feb 08, 2010 11:42 pm    Post subject: Reply with quote

Aaaaaaaaaaaaaaaaaaah of course!!

What a dummy.
Embarassed

So it remains - all DailySudoku puzzles can be solved with standard wings. What a relief. Very Happy
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keith



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

PostPosted: Tue Feb 09, 2010 3:51 am    Post subject: Reply with quote

kragzy wrote:
So it remains - all DailySudoku puzzles can be solved with standard wings. What a relief. Very Happy


There are many, including me, who think this is not a good thing.

Keith
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