Probably the most low-effort blog post I've read in a while

Usually John Cook’s blog posts are extremely high quality, so I’ll give him a pass just this once.

Yeah… I was really interested in thinking about how to code a solution and then the post ended.

It’s not that deep. Same algorithm as for palindromes, but with different logical conditions on “equality” / continuation

Funny enough, I came to the comments section to say how much I enjoy the occasional short post that touches on one thing and moves on.

I don’t need my life to be chock full of deep dives into ideas.

Seems like there isn't much material to expand upon "()()" versus "())(".

I prefer this other article about palindromes:

Was It A Cat I Saw? - https://news.ycombinator.com/item?id=33285198

I had to work harder than expected to get this. I interpret the cartoon as distinguishing between meaning and form. Until I read it aloud, I couldn't stop interpreting the strings as

open close open close

in both directions.

Thanks for explaining this.. I honestly had no idea, even tried to google it.

Perhaps https://youtu.be/qTBAW-Eh0tM at cost of breaking symmetry

I didn't expect to be surprised by this! After thinking about it, it reminds me that game about reading some color names as fast as possible, where the names are painted with another color.

Treating 'u' and 'n' as symmetric is a bit cheating. Luckily, they are also rotationally symmetric words, like 'snus' and 'pod'.

cf https://en.wikipedia.org/wiki/Ambigram

Lower case u not so much because in some fonts it's just a smaller upper case U.

But the y is as symmetrical as j or g.

Yet the uppercase G is symmetric to 6. Case in point: 604.

I always appreciated the rotational symmetry of “up”/“dn” (as seen on some keyboards in the context of Page up and Page down).

Holy shit. T I L.

Interesting choice of ‘snus’ as the example, rather than ‘suns’

UwU

Isn't also the lowercase l and mirror of the upper case I?

There's also the niche use case of vertically arranged English letters — you see this once in a while on signage, but my favorite example is from _Street Fighter 3,_ where the character DeeJay has pants with "MAXIMUM" written down the leg, which means that you can flip the sprite (i.e. to have the character face left or right) and the word stays intact.

> Street Fighter 3

I think it’s Street Fighter Alpha 3, and it happens in a previous game as well: Super Street Fighter II – see https://static.wikia.nocookie.net/streetfighter/images/8/88/... and https://static.wikia.nocookie.net/streetfighter/images/d/dc/...

sf4 as well, but not in 6 yet. one assume capcom will have a "classic" costume pack with that one

wow

The HN crowd does not have sense of humour:)

non

I hope you don't get down voted like the previous comment :)

If 'm' and 'u' are symmetric, surely 'n' is as well?

The name of one of the Indian languages "malayalam" is a palindrome, though not visually symmetric.

According to the rules in TFA, this is indeed “visually symmetrical”

Edit: “For lower case, I will assume the following letters are symmetric: i, l, m, o, u, v, w, x, y.”

> According to the rules in TFA, this is indeed “visually symmetrical”

Only if you ignore case and mix uppercase A and lowercase l.

> Edit: in uppercase only, I suppose

Not even. Uppercase L is not a symmetric character.

poq bod dob qop

How about rotational symmetry?

  qp
  db

  pq
  bd

* * *

“pod” is rotationally symmetric and in the dictionary.

Or vertical:

  p  q  y
  b  d  λ  ;)

"racecar" is a palindrome that you cannot unsee.

I’ve seen it many times but had to reverify when seeing your comment.

Actually "butt tub" is a palindrome that you cannot unsee. Even at a young age I had a very sophisticated sense of humor....

I once made a little puzzle that involves this idea: https://hcs64.itch.io/fitting-words

That was really fun!

Hey that was really good! Took me a minute to figure out the concept and then suddenly 20min was gone, a sign of a good puzzle!

You should totally try expanding on this

I spent a minute thinking ROTOR was impossible until I realized the asymmetry in the ruleset. Neat puzzle.

Fun game! I got stuck on Monotone

I always liked that "yeah" is point-symmetric if you pick the font right.

I don't see how you can allow lowercase "m" and "u" as symmetrical without also by the same principles including "n." In which case there are other words like "nun" and "non." Also "MAM" and "MOM" are symmetrical and are words (at least, Scrabble words. He only includes "MAAM" which oddly enough is not a Scrabble word.)

More along those lines here: http://www.fun-with-words.com/word_records.html

> He only includes "MAAM" which oddly enough is not a Scrabble word.

What's odd about that? ISNT, DONT, ARENT, COULDNT, SHOULDNT, none of them are Scrabble words. More generally, you're not allowed to misspell words in Scrabble.

There's an Swedish fantasy role playing game/novel[0] in which there's a city called HOXOH (all uppercase). It's also known as the "City of Illusions" and home to the magical Academy of Illusionists (who are often practicing their art in the streets). It was given its name partly due to the fact that the word could be read and mirrored in any direction without becoming distorted/assymetric.

[0] The RPG is called Drakar och Demoner (Dragons and Demons) and is roughly the Swedish equivalent of D&D, though it's actually based on the BRPG rules. The supplement that introduced HOXOH was eventually used as a basis for a series of (quite interesting) fantasy novels written by the very author that originally wrote the RPG supplement.

The brand "newman" was a thing when I was a kid.

My mind got blown out the day someone made me notice you could rotate the logo 180 degrees and end up with the same logo.

Wikipedia has the official logo and animation showing it in action:

https://fr.wikipedia.org/wiki/New_Man

You can take words that aren’t naturally symmetric and draw them symmetrically. You get ambigrams, like this:

https://scottkim.com/2020/07/17/origami/

What about cursive, where mirroring/rotating does not even produce the same number of letters? (eg.: google love hate mirror image)