12:53 AM
0

Sliding-block chess puzzles have gone a little cold, so here be a hearty warm-up! ;D In the below position that I created, it Black to move, but there is a twist: the stipulation is that it is a series-mover-helpmate. You may not know what that is, so here's a brief summary. A series-mover i...

1:32 AM
0

This is a Heyacrazy puzzle. Heyacrazy is an original genre, inspired by the "two border" rule of Heyawake and Heyawacky. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. There cannot be a li...

2:04 AM
@Sphinx @Deusovi - perhaps I'm being dense, but I don't understand rule 3 at all... Are the black lines "line segments" or "borders"?

The black lines are "borders". The rule is the same as Heyawake, but now "lines" can go in any direction.
Hold on, let me edit in an example

2:17 AM
@Alconja Example added, and changed the phrasing of the third rule - is it clear now?

Ahh, you're drawing the line segments...
I believe I get it now. Thanks.

2 hours later…
4:18 AM
I assume with Heya* puzzles, I'm not allowed to use logic that says "if Configuration X, then there's a square that could ambiguously be either filled or not, therefore not Configuration X"...

i gave up after 10 mins lol

I did a little when deus clarified rules, but then had to actually do work... coming back for another brief look.

I'm burying myself in making a long story for an upcoming puzzle

@Alconja yeah, in puzzles, logic that relies on the fact that a puzzle has a unique solution is generally discouraged

That's what I figured. Definitely fails the "does it feel like cheating?" test.

5:06 AM
@Deusovi My impression is it's perfectly acceptable in sudoku.
Not sure what I base that impression on, tbh. (And I'm extremely unfamiliar with heya*, so can't speak to them.)

What, really? I've heard the opposite.
Though I don't do much sudoku - not a fan of the genre.

You want to take this outside?
Huh?
Do you?
oh, wait, Poe's law...... let me clarify, that was a joke

don't worry, I got that one
Anyway, the reasons for uniqueless logic being bad in general are:
(1) You can't be sure that your solution is the only solution. (What if there's a mistake in the puzzle?)
and (2) Because the creator couldn't use uniqueness logic, there must be some other logical path built in. If you make deductions based on the puzzle having a unique solution, you skip (/ miss out on) that logical path, which is less fun for both the creator and the solver.
(I would feel no shame using uniqueness logic on a puzzle I knew to be computer-generated. And I probably wouldn't mind using it for Sudoku either, but that's because all Sudoku puzzles "feel" computer-generated to me.)

I'm not sure (2) is correct. Specifically, I recall reading/hearing that there are sudoku puzzles that are designed specifically to be solvable only by use of such steps. I may, however, be misremembering.
Why do you say the creator can't require uniqueness logic?

5:23 AM
Because they have to know that the solution is unique? If the creator used uniqueless logic themselves while making the puzzle, then they're relying on a fact that may not be true about the puzzle they eventually make.

Hm... I've never tried to create a sudoku puzzle at all, but I imagine that that should be doable.

Here's an example with Slitherlink, which I think is easier to see. (Rules of Slitherlink: Draw horizontal and vertical lines between some of the given dots to form a single loop. Numbers tell how many segments of their square are part of the loop.)

(should be doable = not my creating a sudoku puzzle. I mean: someone's creating it with the requirement that the solver rely on uniqueness)
@Deusovi ok, I've found a solution to that one rot13(ybbxf yvxr n ovt ryy), so assuming uniqueness I'm done. You're saying that's insufficient?

Yes, I am -- because this puzzle isn't unique.

ah, fair enough. :-) I didn't read the rules carefully enough, and assumed uniqueness. But for sudoku, I think standard rules include uniqueness, no?

5:28 AM
There's a 2 in the bottom left. That 2 can be satisfied either using both the bottom and left edges, or the top and right edges. (These are the only options; any other configurations of edges around that loop would leave and endpoint stranded in the corner.) By uniqueness, it must be the bottom-left configuration, since if it were the top-right configuration it could just be flipped to the bottom left. This configuration must be forced by the central 2, then, and that gives the loop.
Of course, the problem there is that the answer isn't unique. If you assume the answer is unique, then you only get a single answer. But if I was constructing this puzzle, I couldn't make that assumption, because I would be misled into thinking it was unique.

right, you can't assume the answer is unique when making the puzzle... but that doesn't mean you can't guarantee an answer that's {unique under the assumption that the answer is unique}

So the constructor has to use some other logic when verifying uniqueness. And that logic should be accessible to the solver too.

(they could use brute force to prove uniqueness, but then presumably there'd be some other way of proof too, even if by guess contradiction)

(yeah, brute force is a method they could use, but any puzzle requiring that kind of brute force is bad)

5:33 AM
Then the one you linked to above would still be valid, because you could use that uniqueness to solve it.
All I'm saying is that the same is true for sudoku. (Dunno why I feel like capitalizing Slitherlink but not sudoku. Weird.)

No, it wouldn't be valid - it would break one of the rules of the genre. Just like a Sudoku puzzle with two 8s in the same row in the givens would be invalid, even if it happened to produce a valid answer ignoring that.

Which rule of the genre? Don't forget this is with the rule that I added.

Yes, it would break the rule you added.
Because the answer wouldn't be unique.

The solver must construct an answer that solves the rules of the puzzle (now including uniqueness). He can use the fact that the loop must be continuous to construct it, can't he? He can use the fact that each number must be bordered by that many segments, to construct the loop. So why can't he use uniqueness to construct the loop? It's just another rule like continuity and the number rule.
(Again, assuming we've added a uniqueness rule.)

The solver can do that -- there's no law of physics preventing it, nor will police come to arrest you. But it's "unclean", in a sense - it's not the same thing as just using one of the other rules. The other rules constrain how you draw lines, or place numbers, or shade cells, or whatever. The statement "this puzzle has a unique solution" doesn't: it says nothing about the solution, but instead tells you something about the set of possible solutions.

5:45 AM
True, fair enough; nonetheless, as I mentioned, I recall reading that some sudoku puzzles require to you to use that rule, so... unclear though it feels (to you) you may have to do it (if you ever do sudoku).

Well, you don't have to - you can always brute-force. But a puzzle that pushes the solver to use uniqueness logic is poorly-designed, because it relies on an extra assertion given with the individual puzzle (sometimes implicitly, sometimes explicitly) rather than solely on the rules of the genre itself.
I'm sure there are Sudoku puzzles where that is the intended route to the solution. And those are bad puzzles. Using the assertion that a puzzle has a unique solution is like solving a problem on a multiple-choice test by figuring out that the answer must be even, and then circling the only even number out of the four options.
You haven't really solved the problem if you do that (even if you have technically found the correct answer), and if the problem was designed to be solved that way then it's poorly-made.
(Of course, that may be a good strategy on that type of exam, where the goal is (unfortunately) to get the right answer quickly rather than to completely understand every problem backwards and forwards. But it shouldn't be satisfying to do that.)

CCCC hint 3: The answer is unique.
;-)

thanks. that helps.

(At least, I hope it is.)

well, if it is really useful, you would have pinned it. so obviously, it is not ;-)

6:00 AM
:-)

3 hours later…
9:23 AM
1

This is in the spirit of the What is a Word/Phrase™ series started by JLee with a special brand of Phrase™ and Word™ puzzles. If a word conforms to a special rule, I call it an Independent Word™. Use the following examples below to find the rule. \$\$ % set Title text. (spaces around the text A...

2 hours later…
11:01 AM
2

I went to a play recently. Immediately after the intermission, some cast members sang this short (and terribly written) song: This treatise we sing on this section of stage is not so long as to discourage. It'll draw all your effort out, lessen your boredom: you'll be like a farm machin...

11:40 AM
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This is actually coming from a business place, but it's all about being able to do math tricks, and that's why I'm posting here. I want to implement the following function: f(x)= 1, x ∈ (-∞,0] 2, x ∈ (0,1500] 3, x ∈ (1500,5000] 4, x ∈ (5000,10000] 5, x ∈ (10000,+∞) The problem is I am...

12:00 PM
2

These three belong to three different clubs. First one, very popular, is singles only club. It is closed for new membership. Second one, very useful, is for singles and couples. It is open for new members but very hard to get in now. Unlike the first two, the third Club is diff...

12:14 PM
@msh210 Wouldn't have even come close without the clues and Gareth's ramblings, but the (presumably unique) solution is: MIX TAPES - def: Some homemade presents; cocktail => MIX; 7- => SEPT-, up => T_PES; + a hint of A(bsinthe)

aha!

12:40 PM
@Alconja Thank you!
You're getting there. Note that the "answer" need not be a word. — msh210 2 mins ago
^ Is the puzzle too confusing like this? I mean, will a typical solver assume he's looking for a single word? He's not.
Is there some tag I should use to dispel that assumption?

CCCC: Drone of returned spirit echoed (6)

don't think there is
of course you can always add a sentence in the description like "the answer is a scottish musical instrument"

but i don't think it's correct to assume you need a single word if nothing is specified

Probably not correct to assume, but also not surprising that people would.

12:59 PM
0

Contrary to the lazy puzzler, the creator of this masyu is too ambitious that he adds not only one but two extra stones, so the puzzle is unsolvable. Finish his job for him by removing those additional stones on the board so that the result is a uniquely solvable masyu. Normal masyu rules apply....

@Alconja mur+mur
<
@jafe okay, then. Thanks.

@msh210 Yep. Back to you. :)

Hopefully this one will be quicker...
CCCC: From the Isle of Man?? Reportedly, they're from Manchester (5)

MANCS (~manx)
@msh210 oops, forgot to ping so here it is ^

1:37 PM
@jafe Yep!

CCCC: Cover the cost of soda outside New York university (4, 2)

2:23 PM
@jafe po(ny u)p

darn... maintenance

@msh210 correct!

@msh210 next one pls

1

In my home is a common household object. I securely attached a marking pen to some point on the household object, and I placed a sheet of graph paper next to the pen, so the paper would not move. I then operated the household object in the normal manner, and it drew the pattern below. What is the...

2:50 PM
CCCC: Inside of goal-line edifice is the air that I breathe? (3,1,4)

3.14...

3:03 PM
hey, do anagrams in cryptic clues form the whole word?
like can we do america = *ame +rica
@jafe

that's completely fine, though it's generally more difficult (so you should keep the rest of the wordplay simple)

ok thanks

1

This is a Heyacrazy puzzle. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. When the puzzle is solved, you may not be able to draw a line segment that passes through two borders, and does no...

^ puzzle 2 of... 11 or so? There's no meta with these, just a sequence of logic puzzles that should get harder over time (plus some variants stuffed at the end)

nice

3:36 PM
0

A quick teaser, enjoy! Across 3 Dance bores serious (5) 6 Light angry look (5) 11 Finally asked it to agree (5) 12 Rails - cunning homes of thieves (5) 15 Trap saner design (5) 16 Kingdom with real messy leader (5) Down 1 Earth would heartlessly bear resistance (5) 2 Fruit left precious sto...

4:34 PM
@msh210 Solution to your CCCC is ALL I NEED (substring indicated by "Inside of").

5:14 PM
@GarethMcCaughan Yes, indeed. And the reference (for those who didn't catch it) is to the lyrics of the song "The Air that I Breathe".

2 hours later…
7:12 PM
2

Sometimes it's difficult for outsiders to understand what brings a couple together. What brings each of these couples together? ENTER INPUT ROTOR MOVES TIGER STATS TARGET DENIER LITER SAVER CIGAR STAMP STOPS RECAP DETER CIDER NORSE SITED SENILE MARTS STUNS ...

7:32 PM
0

Three colleagues at the bank are boasting to each other… Colleague 1: “Ask anybody – I’m clearly the best.” Colleague 2: “And how do you figure that?!” Colleague 1: “Well, just mention my name and people instantly think of one thing: ‘quality’ – I’m practically synonymous with i...

8:31 PM
1

This is a Heyacrazy puzzle, originally constructed for a test for Logic Masters India. Rules of Heyacrazy: Shade some cells of the grid. Shaded cells cannot be orthogonally adjacent; unshaded cells must be orthogonally connected. When the puzzle is solved, you must not be able to draw...

9:10 PM
0

Specify the clue in this pattern: 22 12 0 15 18 15 27 26 18 13 8 22 27 13 0