## Sudokus with an original rare shape

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

### Sudokus with an original rare shape

I deem it important to solve sudokus of as many shapes as possible. Most newspaper-sudokus follow all-the-same pattern. That's boring and dulling. Does somebody know one-solutional sudokus with a very rare symmetric shape not easy to find?

Are there special books about exotic looking sudokus?

Here one of my stranger's favorites:

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

Claudia
Last edited by claudiarabia on Tue May 23, 2006 5:48 am, edited 1 time in total.
claudiarabia

Posts: 288
Joined: 14 May 2006

### Hats off!

Here is a link to a cool one (that I didn't create <sigh>, this site has people generated puzzles.)

http://www.sudoku.frihost.net/forum/viewtopic.php?t=475&highlight=hats

If it was mine I'd post it, as it is not, here is the pattern.

Code: Select all
`X . X | X X . | . . X . . . | . . X | X . X X . . | . . X | X X . --------------------- X . . | . . X | X X . X . . | . . . | . . . . X X | X . . | . . . --------------------- . X X | X . . | . . . . . X | X . . | . . . X X . | . . . | . . .`
fermat

Posts: 105
Joined: 29 March 2006

Hi Claudia, what shapes are you looking for
ab

Posts: 451
Joined: 06 September 2005

ab wrote:Hi Claudia, what shapes are you looking for

I'm looking for rare Sudoku-pattern-design. For instance when it resembles a certain figure in live, a bird for instance, means it can give an abstract picture. I like the sudokus with a lean symmetric axis and where the clues are concentrated in some corners whereas other areas were left completely free. It has more contrast and accent then and looks exciting. It should still be one-solutional.

Nevertheless I'm aware of the fact that there must be a compromise between moulding an original-looking pattern and choosing a reasonable number of initially givens, making the solution-finding continuously interesting and not shortening the solving-time to much.

Claudia
claudiarabia

Posts: 288
Joined: 14 May 2006

Try this site

JPF
JPF
2017 Supporter

Posts: 3754
Joined: 06 December 2005
Location: Paris, France

### Re: Hats off!

[quote="fermat"]Here is a link to a cool one (that I didn't create <sigh>, this site has people generated puzzles.)

Yeees, it's coool. I like the shape. And here is another piece of my private collection:

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

I checked also the site
http://sudoku.frihost.net/forum/viewtopic.php?t=656.

It is a real gold mine for good sudoku-seekers. Thank you!
Claudia
Last edited by claudiarabia on Mon May 22, 2006 9:08 am, edited 2 times in total.
claudiarabia

Posts: 288
Joined: 14 May 2006

Simple Sudoku says this puzzle has 32 solutions. Is one of the clues entered in the wrong cell?

The initial clue set of the puzzle in your first post does look cool, but solving with only singles isn't going to hold much interest for most people on this forum.

Tracy
TKiel

Posts: 209
Joined: 05 January 2006

not sure what you're looking for! How do you like this?
Code: Select all
` . . 2 | . . 3 | . . 5  . 5 . | . 7 . | . . .  9 . . | 1 . . | . . .  ------+-------+------  . . 4 | . . 2 | . . 3  . 6 . | . . . | . 1 .  8 . . | 7 . . | 9 . .  ------+-------+------  . . . | . . 5 | . . 7  . . . | . 3 . | . 8 .  2 . . | 8 . . | 1 . . `
ab

Posts: 451
Joined: 06 September 2005

SOLO, a free applet in Simon Tatham's Portable Puzzle Collection, will create puzzles with your choice of 7 different types of symmetry:

2 way rotation
4 way rotation
2 way mirror
2 way diagonal mirror
4 way mirror
4 way diagonal mirror
8 way mirror

... in 6 levels of difficulty.

Micheal Kennett's program allows you to create any template(s) you wish, though the time it takes to find a match can vary greatly.

Here's a few I created just now with a some of my own templates:

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

See Sudoku Patterns for a large number of puzzles with a few interesting patterns, one of which is a pattern I came up with. TSO I has 3 empty rows, 3 empty columns and 3 empty boxes -- a total of 9 empty groups, for example:

Code: Select all
`. . . . 1 2 . 3 4. . . . 5 6 . 7 8. . . . . . . . .. . . . . . . . .4 1 . . . . . 8 52 9 . . . . . 6 7. . . . . . . . .1 2 . . 3 9 . . .9 8 . . 4 7 . . .`
tso

Posts: 798
Joined: 22 June 2005

### I'm sorry

TKiel wrote:Simple Sudoku says this puzzle has 32 solutions. Is one of the clues entered in the wrong cell?Tracy

I checked the doubted sudoku and I found out that my programm tricked on my. When I invented a pattern and tried to reduce the clues afterwards to make it more ambitious I discovered that Sudoku-Drucker remembers the clues I deleted previously. So it showed still one solution even when there were plenty of them suddenly. After this dreadful discovery I turned to load a completely new sudoku before an upgrade of a sudoku in work and then I'm sure, the programm will have forgotten what I did previously. But thanks to the programm-advice of some members I'll overcome this problems I hope.
I tried several times to rectify the sudoku criticized by TKiel but until now I always chose the wrong body of numbers to mould the desired sudoku-pattern out of it. Maybe it doesn't work at all.
Code: Select all
`6 . . | . . . | . 8 .. . 8 | 3 5 4 | . . 7. 3 . | . . . | 2 . .-----------------------. 8 . | . 9 . | 7 . .. 1 . | 5 . . | 9 . 6. 7 . | . . . | 1 . .-----------------------. . 3 | 9 6 5 | . 7 .7 . . | . . . | 5 . 2. 5 . | . 4 . | . 6 .  `

Therefore I created a new sudoku with a pattern I was more successful in and I dedicate it to the alert Tracy:
Code: Select all
`2 5 . | . 7 . | . 8 96 . . | 1 8 . | . 5 .. . . | . . 9 | . . .---------------------. 2 . | 5 . 8 | . 6 .9 6 . | . . . | . . 5. . 3 | 2 . . | . . .---------------------. . . | . . . | 1 . .8 1 . | 3 . . | . . 47 . . | . 6 . | . 3 . `

Claudia
claudiarabia

Posts: 288
Joined: 14 May 2006

### Re: I'm sorry

claudiarabia wrote:
TKiel wrote:Simple Sudoku says this puzzle has 32 solutions. Is one of the clues entered in the wrong cell?Tracy
(...)
I tried several times to rectify the sudoku criticized by TKiel but until now I always chose the wrong body of numbers to mould the desired sudoku-pattern out of it. Maybe it doesn't work at all.

Here are three puzzles - small modifications of the multisolution puzzle:
Code: Select all
`# S6. Easy puzzle, solves with single eliminations only: *-----------* |9..|...|.8.| |..8|354|..7| |.3.|...|2..| |---+---+---| |.8.|.9.|7..| |.1.|2..|9.6| |.7.|...|1..| |---+---+---| |..3|965|.7.| |7..|...|5.2| |.5.|.4.|.6.| *-----------*`

Code: Select all
`# ND. A bit harder, can be solved with naked pairs: *-----------* |6..|...|.8.| |..8|314|..7| |.3.|...|2..| |---+---+---| |.8.|.9.|7..| |.1.|8..|9.6| |.7.|...|1..| |---+---+---| |..3|965|.7.| |7..|...|5.2| |.5.|.4.|.6.| *-----------*`

Code: Select all
`# XY. More advanced. Can be solved with xy-wing: *-----------* |6..|...|.8.| |..8|324|..7| |.3.|...|2..| |---+---+---| |.8.|.9.|7..| |.1.|5..|9.6| |.2.|...|1..| |---+---+---| |..3|965|.7.| |7..|...|5.2| |.5.|.4.|.6.| *-----------*`
Ocean

Posts: 442
Joined: 29 August 2005

tso wrote:
Code: Select all
`. . . . 1 2 . 3 4. . . . 5 6 . 7 8. . . . . . . . .. . . . . . . . .4 1 . . . . . 8 52 9 . . . . . 6 7. . . . . . . . .1 2 . . 3 9 . . .9 8 . . 4 7 . . .`

You can make that pattern more symmetric with some row swapping:
Code: Select all
` . . . | 1 . 2 | 3 . 4  . . . | . . . | . . .  . . . | 5 . 6 | 7 . 8  ------+-------+------  4 . 1 | . . . | 8 . 5  . . . | . . . | . . .  2 . 9 | . . . | 6 . 7  ------+-------+------  1 . 2 | 3 . 9 | . . .  . . . | . . . | . . .  9 . 8 | 4 . 7 | . . . `
ab

Posts: 451
Joined: 06 September 2005

ab wrote:
You can make that pattern more symmetric with some row swapping:

True, but the original pattern has an empty 5x5 square in the center -- the largest possible empty square, as well as a 4x4 empty square upper left -- and it still has diagonal mirror symmetry. (Is 5x5 the largest possible empty rectangle as well?)

A comprimise that keeps the 5x5 empty and adds 180 degree rotational symmetry:

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

Posts: 798
Joined: 22 June 2005

tso wrote:Micheal Kennett's program allows you to create any template(s) you wish, though the time it takes to find a match can vary greatly.
...

Could you give an example on how to use this program. (command lines, etc...)

Thanks.

JPF
JPF
2017 Supporter

Posts: 3754
Joined: 06 December 2005
Location: Paris, France

tso wrote: (Is 5x5 the largest possible empty rectangle as well?)

Here's a puzzle with a 7x4 rectangle:
Code: Select all
` . . 3 | 6 1 9 | 2 . .  . . . | . . . | . . .  6 . . | . . . | . . 7  ------+-------+------  . . . | . . . | . . .  8 . . | . . . | . . 6  . 5 7 | 8 . 2 | 1 3 .  ------+-------+------  . 6 . | 1 4 7 | . 2 .  . . 1 | . 2 . | 5 . .  . . 8 | . 5 . | 3 . . `
ab

Posts: 451
Joined: 06 September 2005

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