Sudokus with an original rare shape

Everything about Sudoku that doesn't fit in one of the other sections

Postby JPF » Thu Jun 07, 2007 1:30 pm

m_b_metcalf wrote:Are there any other symmetric 18-clues puzzles, or are these two the first to be published?

You should have a look here.

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Re: A prize-worth sudoku

Postby gsf » Thu Jun 07, 2007 1:34 pm

m_b_metcalf wrote:
Mauricio wrote:Do you mean sudokus with 17 clues and rotationally symmetric?
I scanned Gordon's list searching for sudokus that are equivalent to a pattern with 17 clues and rotationally symmetric, and none appeared.

Yes, that's what I meant. Thanks for doing the search. Are there any other symmetric 18-clues puzzles, or are these two the first to be published?

I have a background process (slowly) symmetrizing gfroyle's 22M 18s
symmetrization searches each puzzle for the highest order symmetry
in the first 1177855 there are 291 with diagonal symmetry and 409 with 180 rotational symmetry (both order 2)
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Postby m_b_metcalf » Thu Jun 07, 2007 3:47 pm

JPF wrote:
m_b_metcalf wrote:Are there any other symmetric 18-clues puzzles, or are these two the first to be published?

You should have a look here.

Thanks. That thread started the day I joined; I was clearly not paying attention:( .

Regards,

Mike Metcalf
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re: Symmetrically-clued 17s

Postby Pat » Fri Jun 08, 2007 9:07 am

above, Mauricio (2007.Jun.7) wrote:
m_b_metcalf wrote:Yes, but I was wondering about rotational (crossword) symmetry. And is something like the following conceivable?



Do you mean sudokus with 17 clues and rotationally symmetric?

I scanned gordon's list searching for sudokus that are equivalent to a pattern with 17 clues and rotationally symmetric,
and none appeared.


thanks for the update!
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two snakes

Postby claudiarabia » Sat Jun 09, 2007 2:58 pm

Code: Select all
. . 4 . . 5 2 9 .
. 8 . . 1 . . . .
. 3 . . 7 . . . .
. 1 . . 5 . . . .
. . 3 . . 2 . . .
. . . 4 . . 7 . .
. . . . 9 . . 8 .
. . . . 2 . . 1 .
. 7 1 8 . . 6 . .


SE 2,6 r8c5 can be omitted.
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Re: two snakes

Postby m_b_metcalf » Sat Jun 09, 2007 6:38 pm

claudiarabia wrote:r8c5 can be omitted.

But if r1,c3 -> 6 and r1,c7 -> 3, it becomes minimal. And then there's the venomous:
Code: Select all
 . . 7 . . 9 8 3 .
 . 3 . . 1 . . . .
 . 5 . . 8 . . . .
 . 1 . . 6 . . . .
 . . 9 . . 4 . . .
 . . . 2 . . 4 . .
 . . . . 3 . . 1 .
 . . . . 2 . . 6 .
 . 8 2 7 . . 9 . .  SE 7.1


Regards,

Mike Metcalf
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Re: two snakes

Postby Mauricio » Sat Jun 09, 2007 8:06 pm

claudiarabia wrote:Two snakes


The majority of the credit is to the creator of the pattern:
Code: Select all
. . 1|. . 2|3 4 .
. 5 .|. 6 .|. . .
. 7 .|. 8 .|. . .
-----+-----+-----
. 6 .|. 2 .|. . .
. . 9|. . 7|. . .
. . .|4 . .|8 . .
-----+-----+-----
. . .|. 3 .|. 5 .
. . .|. 4 .|. 6 .
. 1 3|5 . .|9 . .   ER 9.1
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Re: two snakes

Postby claudiarabia » Sat Jun 09, 2007 9:47 pm

m_b_metcalf wrote:
claudiarabia wrote:r8c5 can be omitted.

But if r1,c3 -> 6 and r1,c7 -> 3, it becomes minimal. And then there's the venomous:
Code: Select all
 . . 7 . . 9 8 3 .
 . 3 . . 1 . . . .
 . 5 . . 8 . . . .
 . 1 . . 6 . . . .
 . . 9 . . 4 . . .
 . . . 2 . . 4 . .
 . . . . 3 . . 1 .
 . . . . 2 . . 6 .
 . 8 2 7 . . 9 . .  SE 7.1


Regards,

Mike Metcalf


Thank you very much. I was not patient enough to grade it up and make it minimal like this. Thanks also to mauricio. Never thought it will get a high rating like this.

Here is an upgrade of one of my first puzzles - the Loving hearts.
They aren't together anymore and r7c3 can be omitted too.
Code: Select all
. . . 1 . 8 . . .
. . 7 . 3 . 8 . .
. . 2 . . . 6 . .
6 . . 8 . 1 . . 5
. . . . . . . . .
1 . . 6 . 7 . . 9
. . 1 . . . 2 . .
. . 3 . 9 . 4 . .
. . . 4 . 5 . . .
SE 1,5
Last edited by claudiarabia on Sat Jun 09, 2007 6:06 pm, edited 1 time in total.
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The happy End

Postby claudiarabia » Sat Jun 09, 2007 9:57 pm

Code: Select all
. . . 1 . 9 . . .
. . 7 . 3 . 8 . .
. . 2 . . . 6 . .
6 . . 8 . 1 . . 5
. . . . 9 . . . .
1 . . 6 . 7 . . 9
. . 8 . . . 7 . .
. . 3 . 7 . 4 . .
. . . 4 . 5 . . .
The loving hearts united. SE 4,5 2xy, UR type 1

Claudia:)
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Postby Mauricio » Sat Jun 09, 2007 10:23 pm

A variation of the two snakes
Code: Select all
. . .|. . .|. . .
. . 1|2 . 3|4 5 .
. 6 .|. 7 .|. . .
-----+-----+-----
. 3 .|. . 1|. . .
. . 4|. . .|3 . .
. . .|5 . .|. 8 .
-----+-----+-----
. . .|. 6 .|. 7 .
. 1 5|4 . 9|2 . .
. . .|. . .|. . .



Minimal loving hearts
Code: Select all
. . .|1 . 2|. . .
. . 3|. 4 .|5 . .
. . 6|. . .|2 . .
-----+-----+-----
7 . .|5 . 1|. . 8
. . .|. 6 .|. . .
3 . .|7 . 4|. . 2
-----+-----+-----
. . 5|. . .|3 . .
. . 9|. 3 .|4 . .
. . .|9 . 8|. . .    ER 8.5
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Postby Mauricio » Sun Jun 10, 2007 2:03 am

More little variations of the two snakes, minimal.

Code: Select all
 . . 1 . . 2 3 . .
 . 3 . . 4 . . . .
 . 5 . . 6 . . . .
 . . 7 . 2 . . . .
 . . . 5 . 6 . . .
 . . . . 8 . 1 . .
 . . . . 9 . . 6 .
 . . . . 5 . . 8 .
 . . 3 8 . . 7 . .  ER 7.2

Code: Select all
 . . . 1 . 2 3 . .
 . . 4 . 5 . . . .
 . 5 . 6 . . . . .
 . . 7 . 4 . . . .
 . . . 5 . 3 . . .
 . . . . 8 . 1 . .
 . . . . . 7 . 4 .
 . . . . 9 . 6 . .
 . 3 1 4 . 6 . . .   ER 7.2
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Re: The happy End

Postby JPF » Sun Jun 10, 2007 9:10 am

claudiarabia wrote:The loving hearts united. SE 4,5

or separated. SE 8,4 :
Code: Select all
 . 1 . 2 . . . . .
 3 . 4 . 5 . . . .
 6 . . . 7 . . . .
 . 2 . 4 . . . . .
 . . 1 . . 8 . 3 .
 . . . . 3 . 5 . 6
 . . . . 6 . . . 5
 . . . . . 7 . 8 .
 . . . . . . 4 . .


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Helices

Postby Mauricio » Sun Jun 10, 2007 9:48 am

Helix I

Code: Select all
 . . . . . 1 2 3 4
 . . . . . . 5 . .
 . . . . . . . 6 .
 . . . . . 4 1 7 5
 . . . . 2 . . . .
 8 9 5 6 . . . . .
 . 3 . . . . 4 . .
 . . 9 . . . . . .
 7 2 6 9 . . . . .   ER 7.4


Can we eliminate r7c7?


Helix II

Code: Select all
 1 2 . . . . . . 3
 . . 4 . . . . . 5
 . . . 6 . . . 7 .
 . . . 3 . 5 2 . .
 . . . . 6 . . . .
 . . 7 4 . 8 . . .
 . 8 . . . 9 . . .
 2 . . . . . 1 . .
 3 . . . . . . 6 4   ER  9.0
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Postby JPF » Sun Jun 10, 2007 5:32 pm

Mauricio wrote:Helix I

Code: Select all
 . . . . . 1 2 3 4
 . . . . . . 5 . .
 . . . . . . . 6 .
 . . . . . 4 1 7 5
 . . . . 2 . . . .
 8 9 5 6 . . . . .
 . 3 . . . . 4 . .
 . . 9 . . . . . .
 7 2 6 9 . . . . .   ER 7.4

Can we eliminate r7c7?
I don't know:(

here are some variations (easy puzzles) :

Code: Select all
 . . . . 1 2 3 4 .
 . . . . . . . 5 .
 . . . . . . 6 . .
 . . . . . 4 1 7 8
 . . . . 2 . . . .
 4 5 9 8 . . . . .
 . . 1 . . . . . .
 . 8 . . . . . . .
 . 7 4 5 9 . . . .



Code: Select all
 . . . . 1 2 3 4 .
 . . . . . . . 5 6
 . . . . . . 7 . 8
 . . . . . 1 . . 7
 4 . . . . . . . 2
 5 . . 7 . . . . .
 8 . 3 . . . . . .
 2 1 . . . . . . .
 . 7 6 3 4 . . . .



Code: Select all
 1 2 . . . . . . 3
 . . 4 . . . . . 5
 . . . 5 . . . 6 .
 . . . 7 . . 8 . .
 . . . . 6 . . . .
 . . 1 . . 2 . . .
 . 9 . . . 4 . . .
 8 . . . . . 2 . .
 7 . . . . . . 8 6


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Postby Mauricio » Sun Jun 10, 2007 11:38 pm

More on helices

Code: Select all
 . 1 . . . . . . .
 . . 2 . . . 3 . 4
 . 5 . 6 . . . 7 .
 . . . 8 . 5 1 . .
 . . . . . . . . .
 . . 4 9 . 2 . . .
 . 8 . . . 7 . 6 .
 1 . 3 . . . 4 . .
 . . . . . . . 9 .    ER 7.1
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