The Sphinx's Lair

12:31 AM

@GarethMcCaughan , Re:

39 mins ago, by Gareth McCaughan

I'm pretty much 100% confident that I've described a problem that your diagrams sketch a solution to; but only, say, 90% confident that it's the problem you had in mind and that there isn't some more elegant scenario that has the same structure :-).

Gareth McCaughan

yes?

humn

Do you have a different scenario for the same structure? I have a clue question as well.

(Clue question might be simpler:)

Gareth McCaughan

I do not have a different scenario for the same structure. I just wondered whether there was maybe something that didn't involve an infinite number of infinitely small inductors.

What's the clue question?

humn

At one point it had the clue along the lines: The total inductance of the components is infinite.

Gareth McCaughan

mm?

humn

12:34 AM

I didn't think it was necessary and took it out but keep wondering how that might have affected your reaching the solution.

Gareth McCaughan

I don't think it would have made any difference.

humn

Good to hear. I was ambivalent about giving away that it might be fractal.

Gareth McCaughan

I suppose it might have stopped me worrying that there was some not-so-complicated-fractal solution I should be looking for instead of following the "obvious" Sierpinski-gasket path.

humn

And I sooooo muuuuuuch like your going into the scaling question! I hadn't thought of it that deeply, just in terms of fractions.

Gareth McCaughan

It couldn't (for me) have given away that it might be fractal, because "oh, it's going to be like a Sierpinski gasket" was more or less the first thought that entered my head once I actually noticed that there was a question about what the specific circuit was.

If you haven't already read it, you might enjoy J B S Haldane's essay "On being the right size".

humn

12:37 AM

Good leap to think fractal, and Sierpinski at that. Nice how simple generators can produce gorgeous fractals.

Gareth McCaughan

(it's about how things scale)

humn

Allometry uber alles! (That's quoting a disco song, not the 1930s)

Gareth McCaughan

Yup. I reckon p>=0.75 that you know this already, but have you seen what happens if you compute Pascal's triangle mod 2?

humn

the way it looks like a Sierpinski?

Gareth McCaughan

yes

humn

12:40 AM

yes!

Gareth McCaughan

(I actually thought p>0.95 but didn't want you to feel bad if you hadn't seen it before :-).)

humn

I enjoy being transparent.

I might have actually seen "On being the right size" already. Allometry is my middle name.

Gareth McCaughan

That's an unusual middle name.

humn

it grows on you

Gareth McCaughan

ah, but how fast?

humn

12:42 AM

yeh heh yeh heh heh yeh heheheh yeh heh heh yeh heh yeh

latest one that caught me by surprise was that raindrops are impossible

think it was a youtube actually

Why Raindrops Are Mathematically Impossible

►

Gareth McCaughan

ah, yes. they aren't that shape at all.

humn

more like blood platelets? i'm still scratching my head about raindrops

Gareth McCaughan

I realise that I have no idea what shape platelets are. I have always assumed kinda plate-shaped for the obvious reason.

Wikipedia (which is always right except when it's wrong) says biconvex discoids and helpfully adds "lens-shaped".

humn

yeah, i realize i had forgotten whether they're convex or concave on the hidden side

while the iron's hot, though, i'd like to see what you think about the other sierpinski resistance on the web...

Gareth McCaughan

R_E is for "effective resistance" or "edge resistance" or something?

humn

12:49 AM

they went with all equal, i think, so had to add those 1-ohm shut resistors in order to get a "finite" outcome

ocf.berkeley.edu/~wwu/cgi-bin/yabb/…

R_E = "equivalent resistance"

Gareth McCaughan

that's a bit ugly

humn

really! it was disheartening when i was scoping out the puzzle

Gareth McCaughan

there's another page that (from the very quick glance I gave it) uses a "standard" Sierpinski gasket, makes all the resistors 1 ohm, and then asks how the corner-to-corner resistance scales as you take more iterations

humn

and i got 0 ohms at the limit ^ which is pretty cool in itself, that a circuit with infinite internal resistance can have 0 combined resistance

(not really paradoxical, though, as an infinite array of parallel resistors does the same)

Gareth McCaughan

yup

humn

12:55 AM

and, yes, a simple circuit would solve the puzzle you just solved. that's why i put in the bit about treating it like a riddle, which implies that interestingness counts

Gareth McCaughan

incidentally, I am cited in a published paper about resistances in infinite resistor networks, but for a kinda stupid reason.

humn

do tell, sounds amusing in more than one way (also, if it isn't obvious, the sierpinski circuit began as the infinite square grid = 1/2 ohm classic)

Deusovi

hey!

ooh, now I'm curious

Gareth McCaughan

The mathematics society at the university I was at has (had? I haven't kept up) an annual mathematics competition thing called the "Problems Drive". Small teams try to solve informal maths problems under time pressure. The winning team gets to set the next year's problems.

My wife and I won one year, so we set 'em the next year, and one of the questions was the old chestnut about the effective resistance between two nodes of an infinite square resistor network.

And each year's problems and solutions are published in the annual journal/newsletter thing the mathematics society has.

(sorry, I should maybe be clear: this is primarily a student mathematics society. When the actual academic mathematicians get together, that's called the Faculty of Mathematics.)

So, anyway, someone read that, was inspired to think about some problems related to other sorts of infinite grids of resistors, figured out some formulae with horrible infinite series and, I dunno, Bessel functions or something, and published his results. And he cited our stupid little writeup of our stupid little puzzle competition, although I'm sure there must be much better places to find the question we asked there.

(E.g., I bet it's in Doyle and Snell.)

so, as I say, kinda stupid. But it does mean I'm probably the single person on PSE best qualified to solve a puzzle about infinite resistor networks :-).

humn

(you're a walkin-talkin-typin bibliography at times too, Gareth, I just found a PDF of the circuit book you just cited)

hahah, one of my first iterations of the sierpinski circuit was an infinite linear "array" of 1 ohm resistors

using the same ground-at-infinity approach of the square grid, guess what the combined resistance turned out to be between adjacent nodes....

hint: the formula generalizes to fractal dimension

Gareth McCaughan

1:06 AM

I'm not sure I even understand what you mean. Just an infinite chain of 1-ohm resistors?

humn

yes. it turned out to be plain silly

Gareth McCaughan

well, if the answer isn't 1 ohm then something is very broken

Deusovi

The resistance between adjacent nodes? Shouldn't just be 1Ω?

humn

yes, i went to infinity and back just to find that out, but it was reassuring

Gareth McCaughan

:-)

Deusovi

1:07 AM

...were you expecting anything different?

humn

i was hoping!

Gareth McCaughan

at least you got back. In three or more dimensions there's a nonzero chance that you stay lost for ever.

Deusovi

(Also, that was a very poetic way of saying "I wasted a ton of time".)

Gareth McCaughan

no, he literally means he (or at least the currents he was considering) went to infinity and back

though of course the other meaning was also intended

Deusovi

Yeah, I know! But the phrasing made it sound like a long journey, which is what I was commenting on

Gareth McCaughan

1:09 AM

I'm quite sure all of that was on purpose.

humn

i don't even try to sneak things by you two

so much fun to play with how suggestible an imaginative mind can be

(of course, the fun begins at home, as in my mind isn't safe from itself either)

Sphinx

0

Q: The number stalker who nobody loves

I stalk number 2 Not centre of attention Nobody loves me Kind of Nazism But not against religions They try to save me Who am I?

humn

You is back!

We can stop taking turns covering and return to being I.

Gareth McCaughan

so the answer to TGE's CCCC is MAGNIFICENT: MAGNIFI(ed) + CENT=100=10^2. I am not certain that I've parsed the wordplay correctly -- I don't much like "beginnings glorified" as a clue for MAGNIFI -- but I'm sure the answer is right because [...continues]

... TGE posted the sum of letter-values a little earlier (to serve as a check in case it was solved in his absence) and it checks out.

oh, I should ping him so that when he returns he can check for himself: @TheGreatEscaper it's MAGNIFICENT.

humn

1:24 AM

Nice, Gareth! and TGE! I think the Sphinx's Lair is like an Angel's Workshop for CCCs. Really, it's exciting to see the state of the art as it develops.

Gareth McCaughan

I don't think we're particularly pushing the boundaries of the state of the art (with the possible exception of a few of Deusovi's odder clues).

humn

Being a novice, I can't really judge, but it sure seems like a hotbed of new ideas.

Gareth McCaughan

Though a reasonable fraction of the clues here wouldn't be out of place in, say, the Times or Guardian cryptics, so we're doing OK.

humn

Where else do so many creative CCCers get to bounce off each other so rapidly?

Gareth McCaughan

I don't know. But I bet there's at least one mailing list or forum or something used by a non-negligible number of seriously skilled cruciverbalists.

humn

1:28 AM

No doubt there are longer-standing groups but I imagine that the pace here is as quick as it gets.

And that the boundaries are as elastic as they get.

Deusovi

The only other place I know is reddit.com/r/crosswords.

humn

(... argh, i've been trying to patch together a curtain that my favorite (regardless) feral cat just now played swashbuckler on and swung a long rip into... reminds me of the half-plane scalar-proof fallacy that I still might try on you sometime, Gareth, but I'd better deal with one thing at a time for now...)

Gareth McCaughan

actually feral?

humn

(reddit.com/r/crosswords is taking forever to load, is everyone from here checking it out at the same time now?)

Deusovi

(It took me under half a second.)

humn

1:38 AM

(there, now, still they don't get to converse with experts like you, Deuso', in real time)

Deusovi

Hey, I'm not an expert.

humn

More and more all the time, you'll be the last to realize.

(The cat is feral in that it just showed up as a kitten and lives outside. Its temperament is quite domesticated)

Sp3000

@GarethMcCaughan Seems doubly right if you consider TGE's other version of the clue (look up "French square" in TSL)

stacksfiller

The site loaded quickly for me

Deusovi

@humn Show us pictures!

humn

1:42 AM

It's a cutie alright but my computer doesn't take pictures.

Deusovi

Does your phone take pictures?

Gareth McCaughan

@humn you say "so rapidly" but we have maybe five clues a day, but every day each of the major UK broadsheet newspapers has a cryptic crossword with maybe 30-40 clues in it.

humn

my phone barely takes calls

Deusovi

:/

Sp3000

Yeah but Gareth we don't get cross letters :P

humn

1:43 AM

I'm impressed by the rapid feedback more than the total volume.

Gareth McCaughan

oh, sure. I wasn't casting aspersions on the crossword skill of the participants here; just suggesting that for all the alleged rapidity the actual rate of crossword-clue transmission here isn't so very great.

Gareth McCaughan

1:57 AM

CCCC: Eid: odd fest, odd festival (10)

Sp3000

EISTEDDFOD?

Gareth McCaughan

@Sp3000 yup

Sp3000

looks up "eid" huh, another festival, neat :)

Gareth McCaughan

(I thought this one would fall super-quickly, but I don't like to say "this is really easy" because 1. sometimes I think something is really easy and it takes the combined brains of TSL several days and 2. when it really is really easy, saying so is apt to be too much of a giveaway.)

Sp3000

CCCC: Mistake Gates for Jobs? (7)

5

I think in this case it's more that "eid" stood out for me :P but given the surface, I think it's a very nice clue

Gareth McCaughan

2:02 AM

The surface reading of yours is truly excellent unless the clue actually turns out to be about Bill Gates and Steve Jobs.

Deusovi

I'd never heard of an eisteddfod.

@Sp3000 ERR + ANDS

That's an amazing clue.

Volatility

wow

Sp3000

:P little shaky about ERR <-> mistake (as opposed to "make a mistake"), but it seems to be in a lot of thesauruses

stacksfiller

2:20 AM

Wooooooooow

How does one even think of that

That's a fantastic clue

Gareth McCaughan

@Sp3000 Very good indeed.

Deusovi

2:31 AM

CCCC: Originate from grave not set apart (4)

Sp3000

Is the lowercase o for "originate" intentional?

Deusovi

(I apologize in advance.)

@Sp3000 Fixed.

Sp3000

k, just checking it wasn't a devious ploy :P

Sphinx

2:49 AM

0

Q: Hi! What is a Living Word™?

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 a Living Word™. Examples of Living Words™ are: ADAPTING BODIES CANCEROUS DISEASES ENVIRONMENTAL FLOURISHED GERMINATIN...

pattern word-property

Sp3000

3:00 AM

@Deusovi SAVE ddef?

Deusovi

Nope - I don't see how you'd get that

Sp3000

Very loosely :P (mental train went "originate from grave" <-> "rise from grave" <-> "resurrect" <-> "save")

Deusovi

Come on, you know that I don't do things that loosely

Sp3000

Yeah I know, but I'm just lacking in other ideas atm :P

Rubio

3:23 AM

hm.

I get FUEL

Originate (def); from [-] grave [FU(n)E(rea)L] not set apart [NEAR]

which I'm sure is wrong, but hey, it's in there ;)

boboquack

Not bad...

But I don't like the double negative

Rubio

what double negative?

boboquack

from [-] not, set apart

Rubio

(not set apart) = NEAR

from = deletion

there's no double negative

boboquack

yeah, but not set apart could already be [-far]. Feels a bit 'hmm...' to me for some reason.

Rubio

3:28 AM

@Deusovi no comment? :)

Deusovi

It's not correct.

Ankoganit

I heard somewhere that deleted letters must be in order

Rubio

Yeah, I think that's true

It looked good for a minute though hehe

Ankoganit

Wow, Sp3000's clue was wonderful

Rubio

yes, it was

I missed it entirely, off running an errand. hehe

Sp3000

3:31 AM

Aww I can't seem to re-star Gareth's

Rubio

TGE's was finally solved eh

restarred gareth's. I belatedly realized it was probably left there, starred, on purpose. Sp3000's definitely was

Deusovi

Pinning a message is an autostar, so it may not have been

Sp3000

I starred Gareth's after it was taken down, but now if I try to re-star I get "It is too late to undo this operation"

Rubio

well. I (ab)used that fact to restar it, just in case ;)

Oliver

5:56 AM

Anyone like my new community ad?

Sphinx

7:39 AM

-2

Q: Rubik's Cube Solving

What is the best/easiest way to solve a Rubik's Cube? I have watched several video's and I also visited the Rubik's site, but I was never able to solve it!

rubiks-cube

TheGreatEscaper

1:37 PM

in and out for the night, looks to have been a fairly quiet day

Looking forward to another week of school sighs

humn

3:15 PM

When you happen to be awake with a spare moment, @TheGrE, I'm more and more curious about how your Part 2 / mod-3 solution for Prime Circuit Optimisation differs from mine. The more I play with it, and with extensions to higher moduli, the better my waste-1-gate-total-for-the-sake-of-clarity solution looks.

Rubio

4:13 PM

@OilerV I wonder if adding "Take the Tour!" would make it better, but it looks good to me.

Beastly Gerbil

4:33 PM

Can one of the mods take a look at my tag synonym proposal? It's been sitting there for ages

Deusovi

@BeastlyGerbil That's not a mod-specific thing. High-rep users can also do tag syonyms. (I've gone ahead and approved it though.)

Beastly Gerbil

Do they not appear in review queues?

Deusovi

Nope.

Beastly Gerbil

So how do people see them then?

Deusovi

By going to that page you linked.

Beastly Gerbil

4:45 PM

Oh. So thats why it was sitting there unviewed for ages

Deusovi

Yeah. It's kinda weird that that's the only way to see them.

Beastly Gerbil

They should appear in the suggested edit review queues

Let's see if I spark a revolution:

0

Q: Can we have tag synonym suggestions appear in suggested edit review queues?

So someone suggests a tag synonym. How does anyone else know about it? There is nothing on site which says when a suggestion has been made, so no-one knows. And if they don't know about it it can't be approved. It would make so much more sense if these suggested synonyms appear in the suggested ...

discussion review suggested-edits tag-synonyms

Sid

5:44 PM

@Deusovi How is terrible=fell?

Deusovi

I didn't know either until Hugh confirmed it:

Invictus

"Invictus" is a short Victorian poem by the English poet William Ernest Henley (1849–1903). It was written in 1875 and published in 1888 — originally with no title — in his first volume of poems, Book of Verses, in the section Life and Death (Echoes). Early printings contained a dedication To R. T. H. B.—a reference to Robert Thomas Hamilton Bruce (1846–1899), a successful Scottish flour merchant, baker, and literary patron. The title "Invictus" (Latin for "unconquered") was added by editor Arthur Quiller-Couch when the poem was included in The Oxford Book of English Verse. With the message of...

"In the fell clutch of circumstance / I have not winced nor cried aloud."

Apparently "fell" means "terrible", at least in late 1800s literature.

Sid

What's up with people coming up with obscure definition of words these days? I hadn't ever heard fell being used to substitute terrible.

@Deusovi And please explain the second clue as well. I am failing to see what you did there.

Deusovi

"Yaw" means "turn".

A "rood" is a cross in a church.

Put those together and make them go "westward" - to the left - and you get "doorway".

Sid

6:12 PM

-1

Q: Magic square with equal sums on rows, columns and diagonals

. Transcription: In a given magic square, if the sum of number in each row and each column and both of the main diagonals are equal, then the value of x is: 1) 10 2) 12 3) 8 4) 15

magic-square job-interview-question

@Deusovi Do the questions on that paper belong to Maths or aptitude?

Deusovi

Huh, "aptitude"? What do you mean?

Sid

You know, similar Maths stuff, appearing in aptitude tests?

Because, I have an idea as to the source of those questions, I am too lazy to brute force all Maths and aptitude Question papers.

Deusovi

Oh, aptitude tests. I don't think "aptitude test question" is really a well-defined category, to be honest.

Sid

So, that belongs exclusively to Maths?

Those questions make me think of Grade 6 or at most Grade 8, not higher than that...

@Deusovi May, I edit in the source to that question? And rather strangely, it's a Grade 3 level Question. The OP clearly lied about their age when they registered in the site.

Deusovi

Sure, go ahead and edit it in. (And they didn't register at all.)

Sphinx

8:48 PM

0

Q: Do Magicians Really Exist?

Disclaimer: I am not affiliated with the following two users in any way: What I would like to know is: Does the following paradox have a name? What is the fallacy of the argument? If possible, where did it originate? Two logicians, Anne and Bob, are having a conversation. A: If...

logical-deduction puzzle-identification paradox

Rubio

^ I'm .... not sure that's a puzzle at all. It's more a question on logic and semantics.

also, the disclaimer is no doubt driven by > puzzling.stackexchange.com/questions/48702/…

Deusovi

I might type up a meta post at some point about paradox. It seems like most of the questions there either don't need it or aren't good.

Mithrandir

I'm lying.

Mithrandir

9:22 PM

I don't see how this rhymes. puzzling.stackexchange.com/review/suggested-edits/27153

Volatility

@Mithrandir "admit" and "lit"

Mithrandir

@Volatility But 'letters' and 'trains'...

Volatility

I'm still not convinced that tags like that are particularly useful though (except in exceptional circumstances). I didn't get much response from my old meta question about it:

4

Q: Purpose of tags which only describe how a puzzle is presented

There are several tags which do not identify an element relating to the puzzle (or its solution) itself, but rather identify how the puzzle is presented. This is most notable with tags relating to poetry, e.g. poetry, limerick, haiku. The rhyme tag is often used simply as the tag description stat...

discussion tags

@Mithrandir XAXA

Not all lines have to rhyme for there to be a regular rhyming scheme. Think ballads, for instance.

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