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Earl
Joined: 30 May 2007
Posts: 677
Location: Victoria, KS
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 Posted: Tue May 20, 2008 6:01 pm Post subject: Double Fin |
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Two coloring steps will solve this, but there is also a rare "double-finned x-wing" (1) that does it in one step.
Earl
| Code: |
+-------+-------+-------+
| . . 1 | 5 . . | 2 . . |
| 8 5 . | . . 4 | . . . |
| 2 . . | . . . | 1 4 . |
+-------+-------+-------+
| 1 . . | . . . | . . 4 |
| . 3 . | . . 8 | 5 . . |
| . . 6 | 7 5 . | . . . |
+-------+-------+-------+
| . . 8 | 3 7 . | . . 2 |
| . . 7 | . . . | . . . |
| 9 . . | . 2 . | 7 . 6 |
+-------+-------+-------+
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Play this puzzle online at the Daily Sudoku site |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Tue May 20, 2008 7:15 pm Post subject: |
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| I couldn't find a "double-finned X-Wing". But, I did find a Skyscraper that solves it easily in one step. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Tue May 20, 2008 11:30 pm Post subject: |
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| the 3's have it |
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tlanglet
Joined: 17 Oct 2007
Posts: 2468
Location: Northern California Foothills
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| Posted: Wed May 21, 2008 1:08 am Post subject: |
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First, I found a kite on 1 which did absolutely nothing, but then I found both the skyscraper and the coloring on 3 which did the puzzle in.
I am still looking for the double fin on <1>, but it may have been before I completed basics.
Ted |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Wed May 21, 2008 2:25 am Post subject: |
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It's a long slog, but basics get you to here:
| Code: | +----------------+----------------+----------------+
| 6 4 1 | 5 39 7 | 2 8 39 |
| 8 5 39 | 2 1 4 | 369 69 7 |
| 2 7 39 | 69 8 369 | 1 4 5 |
+----------------+----------------+----------------+
| 1 89 5 | 69 369 2 | 3689 7 4 |
| 7 3 2 | 14 469 8 | 5 169 19 |
| 4 89 6 | 7 5 139 | 389 2 1389 |
+----------------+----------------+----------------+
| 5 6 8 | 3 7 19 | 4 19 2 |
| 3 2 7 | 14 469 169 | 89 5 189 |
| 9 1 4 | 8 2 5 | 7 3 6 |
+----------------+----------------+----------------+ |
Look at the possible X-wing on <1> in R58C49. "True" means "is <1>".
1. Either the X-wing is true, or R5C8 is. Either way, R6C9 is not true.
2. Either the X-wing is true, or R6C9 is. Either way, R5C8 is not true.
(Edit 5/21/08: Fixed reference to R5C8, was incorrect as R5C1.)
I think these double fins are quite common.
Keith
Last edited by keith on Wed May 21, 2008 9:12 pm; edited 1 time in total |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Wed May 21, 2008 2:26 am Post subject: |
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I will take a stab at AIC notation here on those 3's, hopefully i get this right. 
(3)r4c5=(3)r1c5-(3)r9c9=(3)r6c9; r4c7 <>3 and r6c6 <>3 |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Wed May 21, 2008 3:24 am Post subject: |
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Norm,
I agree with you if you meant:
(3)r4c5=(3)r1c5-(3)r1c9=(3)r6c9; r4c7 <>3 and r6c6 <>3
keith,
I have no problem with FXW #2. But, #1 has me stumped. r5c1 is a placed <7>. So, that must be a typo. There is no possible Fin in c1. Perhaps you meant r5c8? That would indeed form a FXW that would eliminate <1> in r6c9 if there were no <1> in r8c6. So, I'm still confused. |
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storm_norm
Joined: 18 Oct 2007
Posts: 1741
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| Posted: Wed May 21, 2008 3:28 am Post subject: |
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| how in the world do I confuse a 9 with a 1, typo typo, geez. |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Wed May 21, 2008 3:44 am Post subject: |
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By the way... the term "Double Finned X-Wing" makes me think of something that isn't possible with an X-Wing: a 2-row (or 2-column) Fin. These are only possible with Swordfish and Jellyfish.
Here is a schematic for such a Finned Swordfish:
| Code: | +-------+-------+-------+
| . . . | . . . | . . . |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+-------+-------+
| - - x | - - - | x x - |
| . . . | . . . | . v . |
| - - x | - x - | x x - |
+-------+-------+-------+
| - - - | - x - | - x - |
| . . . | . . . | . . . |
| . . . | . . . | . . . |
+-------+-------+-------+ |
"-" indicates cells that must not contain x. "v" is the victim.
I came across one of these only once. It is not easy to spot. (And such a Finned Jellyfish is REALLY not easy to spot! Though, I suppose it is child's play compared with spotting a Finned Franken Jellyfish! And let's not even talk about Double-Finned Franken Jellyfish.) The Fin is r46c7. The two rows with the Fin must share the same "floor" (horizontal "chute" of 3 boxes).
I'll leave it to readers to figure out why this isn't possible with an X-Wing. (Hint: It has something to do with Locked Candidates.) |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Wed May 21, 2008 9:14 pm Post subject: |
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| Asellus wrote: | keith,
I have no problem with FXW #2. But, #1 has me stumped. r5c1 is a placed <7>. So, that must be a typo. There is no possible Fin in c1. Perhaps you meant r5c8? That would indeed form a FXW that would eliminate <1> in r6c9 if there were no <1> in r8c6. So, I'm still confused. |
Asellus,
I have edited my original message above. If I still do not have it straight, please let me know.
Keith |
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Asellus
Joined: 05 Jun 2007
Posts: 865
Location: Sonoma County, CA, USA
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| Posted: Thu May 22, 2008 12:40 am Post subject: |
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Keith,
That first FXW just doesn't exist as far as I can see. How do you justify the presence of <1> in r8c6? |
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keith
Joined: 19 Sep 2005
Posts: 3355
Location: near Detroit, Michigan, USA
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| Posted: Thu May 22, 2008 9:50 am Post subject: |
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| Asellus wrote: | Keith,
That first FXW just doesn't exist as far as I can see. How do you justify the presence of <1> in r8c6? |
Asellus,
You are correct! I must be blind. 
Keith |
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