Larry Hosken: New

I enjoyed this crossword puzzle's gimmick: https://www.theatlantic.com/free-daily-crossword-puzzle/?id=atlantic_20210221&set=atlantic&puzzleType=crossword

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2021-02-25T14:38:58.227178

I had some thoughts about automatically-generated mazes rattling around in the back of my head and figured out a way to apply an algorithm from that Mazes for Programmers book to a problem I'd noticed a while back.

The problem: I wanted to create a maze with thick walls; and I wanted to choose the maze's entrance and exit squares ahead of time. Alas, the naive algorithms I had were more likely than not to block off the entrance and/or exit with walls. But I'd had Kruskal's algorithm (as applied to mazes) on my mind, and I saw how to apply it here: choose an entrance and an exit, then grow a maze-tree from each; when the two maze-trees collide, treat them as a single maze-tree and continue growing to fill in the rest:

(This problem doesn't show up with normal "skinny-wall" mazes; you can choose any square as the entrance and any as the exit/goal/whatever. You can get from any point to any other point in a normal maze; you can always be assured that there's one way to get from start to finish.)

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2021-02-14T20:49:21.011304

I've been digging these interviews with early employees at tech startups. (Note: I didn't say "with founders"—instead, these are the first hires, wacky risk-takers who maybe weren't that convinced of the vision, but along for an interesting ride.)

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2021-02-13T23:48:11.570643

The US Postal Service announced new stamps for 2021. One title especially caught my eye: "Mystery Message." Wow, a stamp with a hidden message. Sounds like something right up my alley.

[Mystery Message stamp: stylized letters in a variety of colors]

According to the USPS explainer page, this stamp's hidden message is MORE THAN MEETS THE EYE!, as spelled out in a designer-ish semi-readable font. But as any serious puzzler will tell you, that's kind of a shallow mystery. Surely there must be another puzzle in there, an extra-mysterious message, as it were. Some doubters might claim that the USPS wouldn't put a multi-layered hidden message on a stamp. Hmph, those doubters probably still think The Crying of Lot 49 was a work of fiction. Thus, we should examine this design more closely.

First, consider possible Morse code. (No great reason to consider Morse code first. But as my puzzlehunt teammates will tell you, I am quite fond of Morse.) The letters in this stamp's "typeface" are decorated with extra dots and lines. E.g., the M has an extra – on top; that's a Morse T. The O is surrounded by ⸬, four dots; four dots is Morse H. TH sure could be the start of a message. Continuing in this manner yields THERM IETRRMIMMRRNRM which looked kind of promising at first before it devolved into a sort of sleepy mumble.

Next, consider the use of color. The letterforms use nine colors for the message. Any topologist could tell you that four colors would have sufficed. Consider the most obvious indexing scheme: There are 2 indigo letters (M on the first row, second T on the third row). This suggests that our extra-mysterious message has an N (The №2 letter in iNdigo). Continuing in this manner with the nine colors yields nine letters:

N  2 iNdigo
O  2 fOrest green (or mOss?)
I  2 pInk
U  3 blUe
I  2 vIolet
R  2 oRange
Y  2 cYan
D  3 reD
R  2 gReen

NOIUIRYDR. How to order these letters? If this stamp used just ROYGBIV colors, we'd use ROYGBIV order; but the presence of forest green and pink colors suggest we should try something else. But I'm not sure what else, so we can try swizzling the letters around and see what we get. A pessimist might not think much of this idea: Surely that's too many vowels to yield a sensical phrase. But but soon an anagram leaps out:

RUIN IDRYO

To some, that might sound like nonsense. But San Francisco-area puzzle nerds (and Cambridge-area puzzle nerds, one supposes) will of course recognize the last name of Ryan and Christopher IDRYO, designers of the The Hunt for Black Bart’s Hidden Hoard puzzle hunt (in which I played with team Dern Tootin').

I think that's the best solution I'll be able to come up with; but if you find another message, don't be shy about it.

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2021-02-13T01:50:55.666615

New Glasses Selfie

On the day my new glasses were ready, I found my spare pair of glasses. It sure would have been nice to find those a month and a half ago, yep. Anyhow, my new glasses have metal under-rims instead of plastic wire; maybe they won't break so easily.

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2021-02-11T14:29:27.709067

Book Report: Mazes for Programmers

This book is about randomly generating mazes by writing computer programs. Before reading this book, I'd tried randomly generating some mazes, but those mazes hadn't pleased me: too many little nubbly dead ends. This book showed an algorithm (well, a few algorithms) that didn't have so many dead ends. (The secret, obvious when you hear it but I swear not so obvious when you're just staring at a maze and trying to figure out what you don't like about it: have fewer branches in the maze.)

There's plenty in this book: several maze-generation algorithms, tweaks for hex grids, tweaks for 3-D, tweaks for cylinders, tweaks for… Uhm, yeah, there's plenty in this book. I didn't use much of it. I was just looking for this one specific thing! But it's nice to know that if I ever want to put a maze on a Möbius strip, this book has some ideas about that.

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2021-02-01T22:13:46.114386

Book Report: Humble Pi

This book talks about math errors and the consequences that follow. There are errors of engineering, software errors (dear to my heart), and plain old computation errors. Some of these get pretty interesting. E.g., until I read this book, I thought the designers of the Millennium Bridge must be pretty darned incompetent. When pedestrians walked across the newly-constructed Millennium Bridge, it started to shake itself apart. Engineers have known about the "breakstep bridge" problem for a long time; there was no excuse for this to happen to a modern bridge. Except except, as I learned from this book, the Millennium Bridge was shaking itself apart in a new, exciting way. It wasn't bouncing up and down as people stomped on it. Rather, it waggled from side to side as walkers shifted.

I found out about medical calculators, used for lives-are-at-stake calculations like drug dosages. If I haul out my phone calculator and type in 2  3 · 4 , it ignores the second dot and shows 2.34. But it's strange that I hit the · key twice—one of those was probably an accident. Maybe I meant to enter 2.34, maybe I meant 23.4. These fancy-pants medical calculators are more careful: they show a warning about the too-many-dots problem. (The book also discusses a problem that can arise from using too many fancy-pants complex error checkers: if the system gets too complex, that's just more opportunities for errors as layers of a system interfere with each other.)

I found out that the Spurious Correlations website is pretty funny and reminds us that plenty of unrelated things correlate with crime rates, cancer rates, whatever rates; and you should take any pundit's discovery of the true cause of whatever with a big grain of salt. I found out about a project Tommy Flowers worked on after his WWII codebreaking work: ERNIE, a random number generator that generated entropy from neon tubes. I learned… uhm, there's a lot of cool stuff in this book. Recommended; check it out.

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2021-01-25T18:15:30.819359

Occasionally, my web alert for "Hosken" turns up a winner.

Genital shape key to male flies' sexual success

"Male genitals generally, and in Drosophila specifically, evolve very quickly, so we were really surprised to find this weak selection," said Professor David Hosken, of the University of Exeter.

Science Daily

Yes, I have the sense of humor you'd expect of a 12 year old.

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2021-01-18T01:03:48.484308

Book Report: Attack Surface

This novel is a sequel to Homeland and Little Brother. It's OK. It leans pretty hard on your suspension of disbelief; a major plot point involves some programmers being good both at hacking security and some gnarly AI. And there's an attempt at a complex character in a pretty-darned-plot-driven book. And… anyhow, this book is OK.

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2021-01-16T00:56:38.329664

My morning thoughts: Put Stacey Abrams in charge of the vaccine rollout. If anyone can organize that shit, she can.

My evening thoughts: Put Stacey Abrams in charge of the Department of Homeland Security. If anyone can put down this insurrection, she can.

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2021-01-06T23:52:18.578952

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