## by:Leren |
27-Oct-2016, 17:28 | |

Here is another version of Andrew's puzzle. Fairly gentle but Harder than Andrew's puzzle. is.gd/Leren_331_1 In creating this puzzle I discovered that the clue 6 in C6 in Andrew's puzzle is redundant - the puzzle is solvable and no harder. |

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## by: Christoph |
28-Oct-2016, 01:53 | ||

Thanks, Leren. Nice and different puzzle. I used settis and x-wings. |

## by: ghw |
28-Oct-2016, 05:48 | ||

Thanks to Leren for this nice one. Done by x-wings, fishes and setti. |

## by: Jan |
28-Oct-2016, 06:36 | ||

Yes, a worthy extreme! An initial, somewhat unexpected 3-wing leaves two singles that together clear one digit. Now, an x-wing exposes a naked double that solves a number of cells. Then there is an x-wing that triggers a small avalanche, leaving only 19 cells unsolved. You now have a choice of two settis, each of which leads to the solution. |

## by: Augenweide |
28-Oct-2016, 12:23 | Add to this thread | |

First time ever I could make out a "naked double". Enjoyed myself (and your str8ts) | |||

## by:TheWeatherman |
24-Oct-2016, 04:30 | |

@Stefan... from my side a further recommendation how to change generally an existing exteme in a way that it has a completely new appearance: (1) to turn the given puzzle by 90 degrees to the right (or to the left, it doesn`t matter)... thus the horizontal line has become the vertical line, and vice versa; (2) to change the given digits as follows: 1 into 9, 2 into 8, 3 into 7, 4 into 6, 5 stays 5, 6 into 4, 7 into 3, 8 into 2, 9 into 1. The psychological effect will be that the observer doesn`t get reminded by the initial extreme!! |

## by: Leren |
24-Oct-2016, 19:14 | ||

In Sudoku parlance this is called morphing a puzzle (changing the presentation without changing the internal logic). In Str8ts as far as I can see there are 16 morphs of any puzzle: 2 number morphs (change each clue X by 10 - X) and 8 rotation/reflection morphs. In Sudoku any puzzle can be morphed in 4,875,992,432,639 different ways ! Now you can see why Sudoku puzzle creators will never run out of "new" puzzles any time soon. Hope this has been of interest. |

## by: Leren |
24-Oct-2016, 19:21 | ||

Oops, forgot the rotation/reflection morphs in Sudoku. The total number of morphs is 39,007,939,461,119 ! |

## by: Leren |
24-Oct-2016, 19:27 | ||

Double oops ! I had included the rotation/reflection morphs, so we are back to a mere 4,875,992,432,639. Sorry about that. |

## by: Stefan |
25-Oct-2016, 07:28 | ||

Perhaps i should talk to Klaus. By using this, he could do his christmas countdown (which i really hope he will do again this year) with just 2 puzzles... :) |

## by: Leren |
25-Oct-2016, 17:24 | ||

Here is a morph of Stephan's first puzzle. is.gd/stephan331_morph See if it's any easier or harder to solve. Somehow I doubt it :) |

## by: Christoph |
26-Oct-2016, 05:46 | ||

Thanks, Leren. Nice and straight forward. |

## by: Christoph |
26-Oct-2016, 06:16 | ||

When I started to try to produce puzzles on paper without the use of a solver or any other digital help, I used this process: taking a fully solved puzzle (with or without the knowledge of the clues), first I tried to find the obvious UR, then modifying the pattern (by adding or deleting black cells) and turning the puzzle by 90 degrees to avoid that somebody might remember the original puzzle. |

## by: Ulrich |
27-Oct-2016, 09:59 | Add to this thread | |

yes, you may get 16 possible morphs from one puzzle: - rotation by 90 degrees - rotation by 180 degrees - pattern mirroring - number mirroring (x -> 10-x) These 4 morph methods may be combined resulting in 2x2x2x2 = 16 different puzzles. In fact, they are appearing differently, but the way and difficulty of solutions are obviously identical. | |||

## by:Stefan |
23-Oct-2016, 13:31 | |

I changed Andrews Weekly Extreme 331 a little bit, perhaps you want to try this version: is.gd/we331imp Same board, same solution, same black hints. Well, the white hints may differ... |

## by: jgrab |
23-Oct-2016, 14:14 | ||

This version is indeed more demanding. DId know find how to decide hi/lo in row G wothout a chain. |

## by: jgrab |
23-Oct-2016, 14:15 | ||

correction: Did not find ... without |

## by: Christoph |
24-Oct-2016, 03:35 | ||

Very nice extreme puzzle, Stefan. I used Settis, swordfishes, xwings, and many pairs. No chain, no steet interaction needed. (Solving it I did not make use of the original weekly puzzle, because I had not solved that, because i had forgotten to place the clue 1 in G8 when transferring the pattern onto my paper.) |

## by: Jan |
24-Oct-2016, 10:45 | ||

I agree with jgrab, one needs a middle-length chain to disprove one alternative in row G, after a 3-wing and two settis have solved 16 cells. Don't see any x-wings or pairs. |

## by: Cole |
24-Oct-2016, 14:09 | ||

I have used three settis and have gotten 17 solved cells and am stuck. I too do not see any pairs. Perhaps a little hint? |

## by: Christoph |
25-Oct-2016, 02:12 | ||

@jgrab, @Jan: sorry, you are right, a chain is needed to find hi/lo in row G. I had missed two candidates in that row, which had led to G8=1 as a direct consequence of setti 8. @Cole: Later on my pairs were eg F18=45, E38=56,... |

## by: Ben |
25-Oct-2016, 10:58 | ||

A much better version - a lot of singles and hidden pairs needed to 28 solved cells - and then a simple street interaction to solve the hi/lo on row G |

## by: Christoph |
25-Oct-2016, 13:26 | ||

Not using the chain to find hi/lo in row G, I am stuck with 17 cells solved (may be same as Cole): A126,B1256,C35,D12,F6,H69,J568. |

## by: Ben |
25-Oct-2016, 13:35 | ||

Christoph, I think the next thing I saw was a hidden pair in row F. This solved one more cell. |

## by: Christoph |
25-Oct-2016, 15:37 | ||

Ben, G8=16 is not a large gap concerning col 8. Thus how do you manage to remove 1 from F8 to achieve F1=45? Did I overlook something? |

## by: Christoph |
25-Oct-2016, 15:54 | ||

TYPO: correct reading: .....to achieve F18=45? ... |

## by: Ben |
25-Oct-2016, 16:04 | ||

The hidden pair I saw was 28 in F4/F7. |

## by: Christoph |
25-Oct-2016, 17:28 | ||

ok, Ben, thanks. Solves E4 and B7, F4, F7, D7,D6,E6,F5. Solves also G7 and G9 if G789 is low. Very good, looks promising. I shall continue tomorrow morning. I have to sleep now. |

## by: Ben |
25-Oct-2016, 17:58 | ||

Christoph, You should also be able to solve J234 - if not, make sure you made all the eliminations from G1234 (ie. it must be either 1234 or 4567) |

## by: Christoph |
26-Oct-2016, 03:35 | Add to this thread | |

Ben, I have solved it first thing this morning. Exactly as you have explained. solveg J4,J3,J2, thus in total 28 cells solved. Then a very simple street interaction FG starting with G2 and involving a 5-cell-block. Solved. I was too tired yesterday night to do this. Your hidden pair in F47 was an excellent observation and the real key! | |||

## by:jgrab |
23-Oct-2016, 07:12 | |

@ Klaus: Here is my annual goat donation in your name. Please retrieve the certificates from is.gd/Goats_for_Klaus Thank you for your efforts throughout the year! If the other providers of extra puzzles (the "et al."s in TheWeatherman's diction) will tell us what would give them pleasure or make them happy, other forum users will certainly also most willingly express their gratitude this or that way. |

## by: Klaus |
23-Oct-2016, 11:45 | Add to this thread | |

Hi jgrab, thanks a lot, very happy about this. | |||

## by: ghw |
23-Oct-2016, 05:14 | ||

Thanks to Stefan. Solved by accurately elimination in 2 columns. |

## by: CL |
23-Oct-2016, 08:03 | ||

Thx Stefan! Exploiting the obvious UR renders it fairly simple. With deterministic strategies only, rather tricky with a lot of careful eliminations, one wing, and some street interactions. Challenging! |

## by: Christoph |
23-Oct-2016, 13:47 | ||

It was a challenge for me. Finally I needed a short chain to decide 1 in C2 or not. Thanks a lot Stefan. |

## by: Bansalsaab |
23-Oct-2016, 22:00 | ||

No chain needed as such if you don't mind UR. Col 8,9 were keys to ensure A8A9 have solution. |

## by: Jan |
24-Oct-2016, 08:23 | ||

If one doesn't want to use the UR, it seems to me the simplest way forward is to decide on CD9 - one option quickly leads to the solution, the other after some while to a straightforward contradiction (column 4 runs out of digits). But at the point with 6 solved cells, I can't see any further progress that doesn't amount to a chain. |

## by: CL |
24-Oct-2016, 09:28 | ||

@Jan: Depending on your opinion on the usual controversy street-interaction vs. (head-)chain, C8<>2 (4-cell), Jelly-3, B5<>9 (5-cell) & respective in-row analysis have led me to that progress... |

## by: Jan |
24-Oct-2016, 10:58 | ||

I can follow the circle disproving C8=2, but where do you see a 4-wing on 3?! |

## by: CL |
24-Oct-2016, 12:07 | ||

Reconsidering, detailed steps should have been (in-row if not mentioned otherwise, rest should be solver steps): -CD9=38 -D8<>7 -C8<>2 (CD89) -Large gap A3 -C12<>5 -D3<>8 -Large gap D8 -C12<>4 -Jelly-3(1249) -B1=23 -B5<>9 (ABC45) -Solving via J5=9 |

## by: Jan |
28-Oct-2016, 03:44 | Add to this thread | |

Can't follow you on the D3<>8 step, CL. | |||

## by: Berny |
23-Oct-2016, 06:51 | ||

Can anyone explain why this one is a weekly extreme? Only because the solver ist not able to find two singles? |

## by: Stefan |
23-Oct-2016, 12:25 | ||

In a soccer game, when do you score a goal? Right, when the referee tells you so. In fact, we do not know how Andrew rates the puzzles. But it's an extreme because Andrew posted it in this section. No solver can be a indicator for an extreme. I have a solver written on my own, Klaus also has, and some others too. Our solvers are "better" then the (basic) solver Andrew provides here, mine solves every str8ts puzzle, even if it has to guess in some cases. You would need a sort of "scale" to rate a puzzle, and there is no official one until now... Feel free to provide one :) Yes, it was easy this week, but just do it like Klaus: solve it without using candidates, solve it by setting the numbers fro A1 to A9, then B1 to B9... There are many ways to make an "easy" str8ts harder. |

## by: Berny |
23-Oct-2016, 13:04 | ||

Thanks for your answer, Stefan! Til now I thougt the difference between an extreme and "normal" ones is the use of stuff Andrews solver does not provide: Settis/BCA, xwings and larger fishes, street interactions and of course chains. |

## by: ghw |
23-Oct-2016, 13:08 | ||

Berny, look right up at Willi's boast: He has solved his first WE and might be happy about it. |

## by: Klaus |
23-Oct-2016, 16:00 | ||

i too do not know how Andrew rates the puzzles. but from years of experience i'm quite sure its as easy as that: every puzzle that has a unique solution and cannot be solved by his solver is extreme, nothing more. as his solver has, for example, in some situations trouble detecting singles, once in a while a puzzle that needs no higher techniques (like this one) is rated extreme, though we superstar-solvers find it quite easy. i have not the slightest problem with that. indeed solving this puzzle i enjoyed quite a bit. as for my solver, he tells me what techniques he needed to solve a puzzle, and that i use as a rating-system. i rate e.g. a "2 Setti, 1 swordfish, 1 jellyfish"-puzzle more extreme than a "1 Setti, 1 xwing"-puzzle. |

## by: Berny |
23-Oct-2016, 16:25 | ||

Thanks for your answer too, Klaus! By the way: I didn't want to "complain" about this weeks puzzle, I only was interested in knowing how the "rating" works... |

## by: Jan |
24-Oct-2016, 05:43 | ||

I, too, believe that Andrew uses the solver for the rating - with the additional complication that, apparently, the solver used for the puzzle rating is a different implementation so that there have in the past been divergences between them. OTOH, the solver can detect singles - it just has the bug that this doesn't work in 9-cell columns/rows (has the feel of an off-by-one bug) and in certain situations where the contents of a compartment are not yet completely determined, but the single is in the intersection set. I find that annoying, but it is his software and his website... |

## by: Ulrich |
27-Oct-2016, 11:01 | Add to this thread | |

by definition a puzzle is called a "Weekly extreme", if Andrew's solver doesn't solve it. That's it - very simple. Cause Andrew's solver doesn't provide all the low level logics correctly, there are sometimes puzzles which are in fact more in the diabolics range than extremes. Right: it is his software and his website. | |||