Pi Day | Hacker News Reader

Pi Day

en.wikipedia.org

143 pointsthrow0101b94 comments

Ever year, Matt Parker calculates pi, and this year it was the largest manual effort to calculate pi in a very long time[1] . I took part this year, though I didn't end up in the video sadly. It was lots of fun though, and a nice trip to london

[1] https://youtu.be/LIg-6glbLkU

I was there too! It was such a nice vibe :^D

I put together an iPhone app that guides you through all the steps needed to compute Pi to 100 decimal places. Surprisingly enough, this doesn't require any complex math -- just basic addition, subtraction, multiplication and long division. The hardest part is verifying your intermediate results, and the app will do that for you. In testing it, I've been able to compute about 40 digits by hand. The way I look at it, some people climb mountains, and others run marathons... I figured it'd be an interesting challenge to see if I could calculate Pi by hand.

https://apps.apple.com/us/app/pi-100-challenge/id6475694538

Woohoo! We're halfway to Tau Day

[1] https://tauday.com

Halfway to the Tau Day (179th or 180th day of year) is March 29th or 30th depending on your definition of "halfway". Pi day is only 73rd or 74th day of year.

tau day being the 180th day of the year is either perfect or incredibly confusing!

τ = 2π, so you're off by a factor of 2.

and only 6 more days until #HoosierPiDay, 3/20 ;-)

For those that need more context

"On Feb. 6, 1897, Indiana's state representatives voted to declare 3.2 the legal value of pi"

https://www.forbes.com/sites/kionasmith/2018/02/05/indianas-...

Yes I feel so embarrassed if we're beeping out Pi and the message is received and decoded with the aliens thinking "They're still sending <what they call Tau> / 2". Imagine if we received a transmission of e/2. And what is our fascination with base-10 representation of Tau/2 digits anyway?

As a Brit I celebrate it on the 3rd day of the 14th month

Not the 31st of April?

I mean now you mention it that might make more sense, but we're a simple people bound by our traditions.

This genuinely made me happy. May the Fourth be with you! Wait…

I celebrate Pi-approximation day on the 22nd of July

3.14 is about 0.00159 less than pi, whereas 22/7 is about 0.00126 greater than pi, making pi approximation day closer to pi than pi day.

This is the research I come here for.

Sure, but by undershooting you can simply wait until the time is 1:59:26.53589793 to celebrate.

Every day is pi-approximation day. It’s just a question of how good the approximation.

The day 1131/12/30 yields 3.1416 repeating.

According to my calculations, the most approximate Pi ISO day expressed literally is 311/9/11 = 3.141414... Of course 311/11/9 also works

132/3/14 = 3.142857142857143. Not bad!

A 355 day lunar calendar would allow for 355/113, which is pretty good.

That would be February 3rd, no?

An apt comment on the horrid US-ian date format. Although the international notation, YYYY-03-14, which is de rigueur for political correctness, would side with the 14th of March.

> YYYY-03-14, which is de rigueur for political correctness

I like it just because I can use it in filenames and sort by name and I'm guaranteed to get it in chronological order.

I celebrate it on the 31st of April, like normal people.

It's in today's NYT connections puzzle:

https://www.nytimes.com/games/connections

I love the NYT Connections game, but some days it makes me feel like an absolute idiot because I can't get a single group correct and am puzzled when the solutions are revealed :D

Together with globle, travle, worldle, framed and gamedle these couple of games are what I play during my morning coffe break, and I'm glad that they exist.

If I feel like more I also try to solve boxofficegame and tradle, but I can't solve them often.

A lot of them need knowledge of USA culture and American English phrases. That's usually what I fail on.

Yeah that's true, was an issue on todays Connections as well :/

Watching a lot of American television, I'm normally OK, but what got me recently in connections is that apparently Jelly Beans are associated with Easter in the USA... that was a completely new revelation to me.

Add Dadagrams to your list: https://dadagrams.com/

No affiliation, it was posted to HN a while back and that is how I found it. The premise is fun, you're playing against the developers dad.

Thanks for the tip! Just played it and was absolutely destroyed by a random dad. I'm really not good at these word-based games, my strength is Globle and Travle. But Dadagrams is fun, added it to my bookmarks ;)

Are moo and new supposed to be homophones of μ and ν?

Apparently... I don't understand why it wouldn't be "mew" and "new"

I have to say the connections this time was particularly poor. Even with the answers I don't get it

What do Day-O and Jackie-O reference? Why are they linked to Daddy-O and Jell-o? Random works that end in -O sometimes in obscure situations?

> Random works that end in -O

Not random, but otherwise yes, end in O. But someone above said you have to be an American to get these and I generally agree.

Daddy-o: a 50s hipster term

Day-o: a song by Harry Belafonte

Jackie O: Onassis, wife to President John F Kennedy

Jell-o: a longstanding dessert mix

Day-o is a pretty deep cut for anyone. I realized they probably wanted Jell-O and other 'things that end in -o', but I couldn't think of the others.

Beetlejuice fans will recognize it easily: https://www.youtube.com/watch?v=AQXVHITd1N4

Also a slickly executed theme on today’s Puzzmo crossword: https://www.puzzmo.com/today

(Zach Gage’s puzzmo is a great collection of daily puzzles if you’re a Wordle/Connections player who craves more)

Plugging the Pi Day Challenge, an online puzzle math quest all about pi created by my high school math teacher, Mr. Plummer (aka Plum). He’s been updating it with new puzzles for the past 15 years with the only goal of getting students excited about math.

It requires a login to save your progress which I know a lot of people dislike here… but it’s worth checking out: https://www.pidaychallenge.com/

Is it just me or is puzzle 24 still locked?

“Pi Day” is a fake holiday invented by Big Math to sell more math.

It was invented by Dominoes to sell more pizza.

Perhaps we might proclaim all of March to be Biblical Pi Month in solemn remembrance of the declaration made in 1 Kings 7:23 and 2 Chronicles 4:2 that PI = 3.

Also consider a semicircle of diameter D. Here the outside of the semicircle S, is D * PI / 2, so PI = 2 * S / D.

Now instead of a single semicircle, consider two semicircles, each of diameter D/2, stacked on top of each other so their diameters line up to add to D. Each has a outside S/2, so once again PI = 2 * S / D.

Now do it for 4 semicircles each of diameter D/4. Again, PI = 2 * S / D.

Now continue to infinity. Eventually the outsides of the stacked semicircles will, at the limit merge to the diameter. Thus at the limit PI = 2 * S / D = 2 * D/D.

Thus PI = 2. Maybe Pi Month should be February? I will leave that to the religious and mathematically inclined to argue.

Would have been more entertaining if the "Oppenheimer" movie had been made about Frank Oppenheimer [1] -- a younger brother of J. Robert and the founder of the Exploratorium museum in San Francisco [2], where Pi Day comes from [3]

[1] https://en.wikipedia.org/wiki/Frank_Oppenheimer

[2] https://en.wikipedia.org/wiki/Exploratorium

[3] https://en.wikipedia.org/wiki/Pi_Day

For purists, there's Pi Second: 3/14 1:59:23.

Not precise enough? You can go to Pi Millisecond, Pi Nanosecond, as far as you want to go. You don't get to enjoy them for long though...

1:59:27, no? Or even 1:59:26.5 if we want to get more precise!

Argh. Yes.

My clock is only able to match four decimals... 15:00 :(

I like Pi first, you don’t have to worry about getting too full for pi that way.

It's a special kind of person who cares enough about math to celebrate "pi day", but not enough to be disturbed by the approximation of 3.14.

Even NASA only uses 15 digits because anything beyond that is unnecessary even at Universal scales.

Also if you want to be really picky, you can celebrate at 1:59 and 29 seconds.

27 seconds! :)

I'd thought 26, but I wasn't rounding properly. I've heard it as "thirty-four seconds before two o'clock", to obscure what time it actually refers to.

a) 3/14 = 0.21428571428 b) If I take reasonable date formats, it's date 2024-03-14 = 2007 today

But kudos for only taking the first three digits, 3.14, as approximation for pi, which is in nearly all cases enough. Some friends in automotive engineering even tried using pi = 3 and 2*pi = 7 for a while, and the results were good enough.

You also have 22nd July the pi approximation day, which is also mentioned in Wikipedia and much more accurate.

And November 10th (November 9th, this year), as the 314th day of the year.

You can find quite a few excuses to eat pie.

I generally do not need an excuse to eat pie.

Your mileage may vary.

Much more? Or slightly more.

If the number of digits in x/y and number in a decimal version are the same, the accuracy is approximately equal

You are correct. In hindsight I was quite tired back then and probably thinking of 355/113 or an average between 3.14 and 22/7 (~= 3.14143) instead...

6 digits vs 6 digits, works again

2*pi = 7 is impressive, given that 6 would be closer. Thats dedication to having bad approximations haha.

> Some friends in automotive engineering even tried using pi = 3

Did they end up with engine cylinders that were hexagonal in cross-section?

Today is 14.03. where I live....

Unfortunately there isn't a 31st April.

Who uses a dot to separate day and month?

14/03/2024 and 2024-03-14 are already 1 format too many...

People that use / to separate hours and minutes.

I wrote that comment on 14.03.2024 at 14:55:00

I think you mean 0/55/2

A lot of people use. I think it is common at least in Europe but probably varies by country.

I found the list on Wikipedia: https://en.wikipedia.org/wiki/List_of_date_formats_by_countr....

So some of Eastern Europe and Scandinavia.

d.m.y is used in several country across Europe (most certainly in Germany, Austria, Switzerland)

Each pi day I get excited for a new Vihart video.

https://www.youtube.com/watch?v=2a9YgCCQYVI

Pi Is (still) Wrong.

https://www.youtube.com/watch?v=jG7vhMMXagQ

It's also the birthday of Albert Einstein (1879).

Also Karl Marx died on 14th of March.

The wikipedia page on approximations of π contains a lot of fascinating results and historical tidbits: https://en.wikipedia.org/wiki/Approximations_of_%CF%80

I see your Pi Day and raise you White Day[1].

[1]: https://en.wikipedia.org/wiki/White_Day

Google has a cute pi day Easter egg on the search calculator.

A bit late but a note for next year:

Entemann’s snack pies are square…

It should rather be on the 116th day of the year, because 365/π ≈ 116, so around 28th of March (27th in a leap year).

As one of my math teachers would remind me, don't forget about 22 June, Pi Approximation Day!

July 22 I think

You 1-based indexing people.

0-based indexing would celebrate in August.

Who said anything about 0-based indexing?

I start counting everything at two, 'cause I'm always number one!

Aw, bummer. You're right of course.

Congrats to all of those who received their MIT acceptances

But July 22 is more than four months from now.

Can't wait for e day on February 71st.

As a reminder, Pi Day is a doomsday!

https://en.wikipedia.org/wiki/Doomsday_rule

my mom turns 90 today!

But July 22 isn't for another four months.

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