Totally OT: Colliding blocks that compute pi

[Sylvia Else]

[yeti]

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

The older videos about this way to get PI are among my favourite PI day
videos. \o/

I haven't seen this update yet. So far I only bookmarked it in my RSS
feeds for somewhen later.

[yeti]

Apropos PI day ... there is a PI related example in 9front's dc.1 man
page ...

<https://tio.run/##***@bm/mL3sYNYN4TWqVWYX9/***@nrcSf28yHANkcDX/***@rEmUQRpgqR5hwJc4oEDo8cYbroGGQwm6oSWmERfjiJlKBDG7kVCo38UvhZpQcTrRcKu4PhBUmlyu6LLMlMSPKE2HZNbExT2kwikGrZOn9lN3YUm6FY0capBKLOo8fXgh@m2L8Aw>

------------------------------------------------------------------------
# pi example from 9front's dc.1 man page
#
1 sq 180 sr 60 st 2 si [ 3 li * 1 + d 1 + * 3 * su li 27 * 12 - lq * 5
lr * + lt 5 * / d 48 + P sy 10 lq li d 2 * 1 - * * * 10 lu lq li 5 * 2 -
* lr + ly lt * - * * sr sq lu lt * st li 1 + si lm x ] sm lm x
------------------------------------------------------------------------

Do the used constants trigger someone's memory about which algorithm
that may be?

I do like playing with DC, but turning others' un-commented code back to
readable maths so far was not among my just for fun DC puzzles.

[Don Y]

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Too funny!

These "practical" examples (for some notion of "practical")
are always entertaining.

Hawkins' "Genius" series includes a number of such demos.
I particularly enjoyed the "time travel" episode and the
"self-assembling molecules" demo.

But, my favorite "in practice" example is the whispering
gallery at the Museum of Science and Industry in Chicago

<Loading Image...>
(The *far* focus is just visible in the background)

(I imagine they exist elsewhere -- I can't recall if the Smithsonian
had one when I last visited. Grand Central Station also has one
but I don't think it was "by design"... more serendipitous)

[The Chicago museum is an amazing asset! A "must see" any time I had
guests in town!]

It is hard not to giggle as you encounter dozens of noisey tourists
walking all around you, talking loudly -- yet can hear your cohort
whispering ~20+ ft away, facing back-to-back!

When I was younger, I enjoyed seeing similar results in the design
of theatrical light sources (ellipsoidal, parabolic, etc.). But
they are nowhere near as dramatic!

[Don Y]

Post by Don Y
These "practical" examples (for some notion of "practical")
are always entertaining.
Hawkins' "Genius" series includes a number of such demos.

s/Hawkins'/Hawking's/

Post by Don Y
I particularly enjoyed the "time travel" episode and the
"self-assembling molecules" demo.

[Lawrence D'Oliveiro]

Did you know you can compute π just by dropping a needle?

<https://en.wikipedia.org/wiki/Buffon%27s_needle_problem>

[yeti]

------------------------------------------------------------------------
~$ gdate -d@$(printf "%d" 0x7fffffff) +%H.%M
03.14
------------------------------------------------------------------------

Easy to remember, eh?

But I still prefer 355/113.

.-----+-----.
.----+----. | The END |
| Repent! | | is neigh! |
·----+----· ·-----+-----·
| _ _ _ |
|\°v° °v° ò.ó/|
|_|\/|_|) /|_|
----------------------------^-^--^-^-----^-^----------------------------

[brian]

In message <***@tilde.institute>, yeti <***@tilde.institute>
writes

Post by yeti
------------------------------------------------------------------------
03.14
------------------------------------------------------------------------
Easy to remember, eh?
But I still prefer 355/113.
.-----+-----.
.----+----. | The END |
| Repent! | | is neigh! |
·----+----· ·-----+-----·
| _ _ _ |
|\°v° °v° ò.ó/|
|_|\/|_|) /|_|
----------------------------^-^--^-^-----^-^----------------------------

I just remember 3.14159 - close enough for government work .

Brian

[SH]

Post by brian
writes

Post by yeti
------------------------------------------------------------------------
03.14
------------------------------------------------------------------------
Easy to remember, eh?
But I still prefer 355/113.
                                      .-----+-----.
                    .----+----.       |  The END  |
                    | Repent! |       | is neigh! |
                    ·----+----·       ·-----+-----·
                         |  _    _       _  |
                         |\°v°  °v°     ò.ó/|
                           |_|\/|_|)   /|_|
----------------------------^-^--^-^-----^-^----------------------------

I just remember 3.14159 - close enough for government work .
Brian

How I wish I could calculate pi

3.141592 - close enough for rocket science! :-)

[Lawrence D'Oliveiro]

Post by SH
How I wish I could calculate pi

Your computer can do it!

import decimal

Dec = decimal.Decimal
decctx = decimal.getcontext()
decctx.prec = 64

def decimal_pi():
with decimal.localcontext() as decctx :
decctx.prec += 2 # extra digits for intermediate steps
t = Dec(3) # substitute 3.0 for regular floats
lasts, s, n, na, d, da = 0, 3, 1, 0, 0, 24
nr_steps = 0
while s != lasts :
nr_steps += 1
lasts = s
n, na = n + na, na + 8
d, da = d + da, da + 32
t = t * n / d
s += t
#end while
#end with
print("nr_steps = %d" % nr_steps)
return +s # unary plus applies the new precision
#end decimal_pi

print(decimal_pi())

output:

nr_steps = 104
3.141592653589793238462643383279502884197169399375105820974944592

Taken from a presentation I did here
<https://github.com/HamPUG/meetings/blob/master/2022/2022-11-14/ldo/Continued%20Fractions.ipynb>.

I tried continued fractions, but found them a waste of time.

[Sn!pe]

Post by yeti
.-----+-----.
.----+----. | The END |
| Repent! | | is neigh! |
·----+----· ·-----+-----·
| _ _ _ |
|\°v° °v° ò.ó/|
|_|\/|_|) /|_|
----------------------------^-^--^-^-----^-^-----------------------

Nay, nay, Neddy, you daft donkey.

[john larkin]

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Pi keeps showing up uninvited.

[john larkin]

Post by john larkin

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Pi keeps showing up uninvited.

Loading Image...

[Sn!pe]

Post by john larkin

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Pi keeps showing up uninvited.

<Loading Image...

An eul spill?

[brian]

Post by Sn!pe

Post by john larkin

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Pi keeps showing up uninvited.

<https://www.dropbox.com/scl/fi/evfwgzx10g1if5kvk2haj/SidewalkGraffiti.
JPG?rlkey=p3r4dlvzqk5g45r7sy1ojtirw&raw=1>

An eul spill?

Hamilton was guilty of a bit of graffiti in his day.

<Https://www.irishtimes.com/news/royal-canal-bridge-stands-as-an-old-uniq
ue-mathematical-shrine-1.318509>

Brjan

[Lawrence D'Oliveiro]

Post by brian
Hamilton was guilty of a bit of graffiti in his day.

Aren't we glad that wasn’t the only place he wrote up his discovery ...

“I have discovered a most marvellous proof, but this bridge is too small
to contain it.”

[Tom Del Rosso]

Post by john larkin

On Tue, 18 Mar 2025 16:05:33 +0800, Sylvia Else

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Pi keeps showing up uninvited.

https://www.dropbox.com/scl/fi/evfwgzx10g1if5kvk2haj/SidewalkGraffiti.JPG?rlkey=p3r4dlvzqk5g45r7sy1ojtirw&raw=1

e^(2pi)i = +1

Shoulda been 6.28

[john larkin]

On Sun, 23 Mar 2025 05:09:08 -0400, "Tom Del Rosso"

Post by Tom Del Rosso

Post by john larkin

On Tue, 18 Mar 2025 16:05:33 +0800, Sylvia Else

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Pi keeps showing up uninvited.

https://www.dropbox.com/scl/fi/evfwgzx10g1if5kvk2haj/SidewalkGraffiti.JPG?rlkey=p3r4dlvzqk5g45r7sy1ojtirw&raw=1

e^(2pi)i = +1
Shoulda been 6.28

We have terrible graffiti thugs in San Francisco.

[Lawrence D'Oliveiro]

Post by Tom Del Rosso
Shoulda been 6.28

I tought I τ a puddy-tat ...

[candycanearter07]

Post by john larkin

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Pi keeps showing up uninvited.

Pi is hidden in a lot of things.

[piglet]

Post by candycanearter07

Post by john larkin

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Pi keeps showing up uninvited.

Pi is hidden in a lot of things.

https://xkcd.com/687

[candycanearter07]

Post by piglet

Post by candycanearter07

Post by john larkin

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Pi keeps showing up uninvited.

Pi is hidden in a lot of things.

https://xkcd.com/687

There really is a XKCD for everything.

[yeti]

Post by candycanearter07

Post by piglet

Post by candycanearter07
Pi is hidden in a lot of things.

https://xkcd.com/687

There really is a XKCD for everything.

Indeed! \o/

<https://xkcd-search.typesense.org/?xkcd%5Bquery%5D=everything>

[candycanearter07]

Post by yeti

Post by candycanearter07

Post by piglet

Post by candycanearter07
Pi is hidden in a lot of things.

https://xkcd.com/687

There really is a XKCD for everything.

Indeed! \o/
<https://xkcd-search.typesense.org/?xkcd%5Bquery%5D=everything>

Good to know theres a search if I ever need it ;)

[Scott Dorsey]

Post by candycanearter07

Post by john larkin

Post by Sylvia Else
http://youtu.be/6dTyOl1fmDo

Pi keeps showing up uninvited.

Pi is hidden in a lot of things.

So much of that is the fault of Euler's identity.
--scott

[Joe Gwinn]

I'm having problems with Agent, where a new Usenet posting has no
subject or way to provide it.