
Dice Become Ordered When Stirred, Not Shaken - ingve
https://physics.aps.org/articles/v10/130
======
ajarmst
More accurately, cubes pack more closely when agitated one way than another.
The fact that they are dice is irrelevant (they don't become ordered with
respect to the facing side). To be honest, this isn't particularly odd, as the
experiment removed the component of the agitation that would tend to displace
the cubes vertically, which is the only dimension with an asymmetric force
that would tend to increase the packing factor if undisturbed (gravity).

~~~
wonderous
Dice are not perfect cubes, since there edges and corners are rounded, so it
would not make sense to generalize the results of dice as applying to perfect
cubes.

~~~
lambda
Casino dice are actually cubes, at least as close as manufacturing tolerances
of 0.0001 inch can make them. For example:

[https://www.casinosupply.com/collections/casino-
dice/product...](https://www.casinosupply.com/collections/casino-
dice/products/new-casino-dice-serialized-3-4-inch-set-of-6)

This is to help make it easier to spot alterations or flaws which could affect
their randomness; shaved corners become very easy to spot, when packing them
together it's easy to spot ones with height differences, etc.

~~~
wonderous
Tolerance you’re referencing relates to the distance of one side to another,
not the shape of the corners; the dice you linked to have their corners
rounded (aka shaved) if you look at the image.

~~~
mohn
Indeed. I think anyone who has done some work with a milling machine will know
firsthand that a freshly cut 90 degree edge that has not yet been rounded over
is sharp like a blade.

If casinos actually did use dice that were extremely cubic, the dice would be
cutting patrons' fingers and wrecking the felted surface of the craps table.

~~~
gambiting
Funnily enough, the website the parent linked actually calls them "
Transparent with razor sharp edges" so I guess they are pretty sharp.

~~~
mohn
I may have been wrong in my previous post. Apparently "razor" is one of
several styles of dice edge and is intended to prevent excess tumbling, so a
craps throw doesn't take too long to come to rest. I'm tempted to buy some new
razor dice to see for myself.

I can't find measurements for the radius of curvature on razor dice edges, but
I'd be surprised if they're truly as sharp as claimed. Without even
considering the liability aspect, it seems inconvenient for a casino to pause
the game because someone is bleeding on the table or dice.

I also wasn't able to learn how often the felt of a craps table is changed,
though I came across something that said the felt's useful lifetime is
prolonged by a foam rubber underlayer.

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dahart
When I'm measuring my food, I like to shake it, so I can fit more in the
measuring cup without increasing the calorie count. ;) Oatmeal will pack down
quite a bit with some shaking.

The title is funny. I realize it's sometimes hard to translate and summarize
scientific results for the layperson, but the paper wasn't comparing stirring
or shaking. They compared rotating the container to tapping the container.
Rotating is, ironically, a type of shaking, and closer to shaking than
tapping. I would expect a good deal of dice packing in this experiment using
vertical shaking, as opposed to lateral tapping.

~~~
kinkrtyavimoodh
That's why you always use a weighing scale :)

~~~
dahart
Yeah, but then I wouldn't get to cheat. :P

~~~
lisper
Try putting your thumb on the scale when you turn it on. ;-)

~~~
AnkhMorporkian
"Honey, why are your hundred grams of oatmeal taking up 5 bowls?"

"I'm not sure! It must be exceptionally light."

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nerdponx
I think their definition of "ordered" is different from most people's when it
comes to something like dice. Cool effect, but it makes for a pretty
misleading headline.

~~~
bkanber
You have to apply the context before you call the (correct) headline
misleading. This is a physical sciences context so this is the correct use of
"ordered" \-- as in "order and disorder", i.e. symmetry and correlation.
You're talking about "ordered" as in "ordinal", meaning "related to position
in a series", which makes more sense in a computer science context (and we are
on HN), but still -- it is your job to apply the context to the situation, not
anyone else's.

~~~
Terr_
If it's all about bloodless scientific rigor, why'd they choose to highlight
"Dice" in the headline when it is probably a property of "cubes" in general?

I'm imagining some biologists studying how human cells have some unique
negative reactions to C3H8O, and then they title the a report "Humans just
can't resist alcohol."

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herodotus
A very well-known parlour trick with dice is called "dice stacking" \- here is
a nice youtube video showing how to do this:
[https://www.youtube.com/watch?v=ZLtOVFE3mYc](https://www.youtube.com/watch?v=ZLtOVFE3mYc)

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wonderous
Paper is titled, “Experimental Study of Ordering of Hard Cubes by Shearing” -
does anyone have a link to the paper as a PDF?

~~~
selimthegrim
Doesn't seem to be on arxiv but here's a conference abstract - ignore the
certificate warning

[https://fises17.gefenol.es/media/contribution/abs-
fises17-as...](https://fises17.gefenol.es/media/contribution/abs-
fises17-asencio.pdf)

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SubiculumCode
I was blown away until I realized that they did not mean that all the face-
values of the dice become aligned.

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gjjrfcbugxbhf
Ordering alignment of rectangular prisms under simple shear is well
established by now.

As is the variable effects of shaking - can increase or decrease packing
fraction and order depending on magnitude.

In addition ordering in packings of rectangular prisms extend up to 8 particle
lengths from the side walls - and are variable with time and history. This
experiment's results could be partly due to edge effects.

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lukasm
any youtube mirrors? videos don't work.

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bertr4nd
I wonder if there’s any insight here that could be applied to optimization via
simulated annealing.

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JoeAltmaier
It took .5g to get the effect. But the dice in the center never aligned.
Probably because, so near the axis, they never experience anywhere near .5g.

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rbanffy
It's kind of applying the Bogosort method in the physical world, with the
exception the physical world favors it.

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microcolonel
I suspect this phenomenon is already in use in material science and
manufacturing.

~~~
Hupriene
That's what I was thinking. Vibratory sorting/feeding machines are common and
a lot of engineering effort has gone into optimizing them. I'd be very
surprised if rotary oscillation had not been tried, and probably used, on many
occasions.

~~~
mattmanser
I have a friend who's got a doctorate in CS. He always adamantly insists his
work was utterly pointless as any company interested in solving the problems
he solved would simply throw people at it and solve it independently in a
couple of months, they'd never find his work.

~~~
skybrian
Sounds like a search problem. I wonder why sharing knowledge works so well
when using Stack Overflow but not for his research results?

~~~
21
Because the purpose of research is to produce papers, not disseminate
information or help others.

See how many CS papers talk about various algorithms without also providing
the source code of said implementation.

~~~
skybrian
OK, but for any individual researcher (such as the original poster's friend)
what if they want to try harder?

~~~
21
Add a github repo with a permissible license, write a blog post, add a stack
overflow answer to some relevant questions.

~~~
bertr4nd
To be fair there aren’t many questions on stack overflow about, “How can I
design my hyperblock selection algorithm for improved performance on a block-
structured data flow processor?”

~~~
derefr
There might be if you first go out of your way to answer questions about
dataflow throughput by pointing people toward block-structuring and mention
keywords like "hyperblocks" there. People already do this; I've noticed a good
few times now that I've done a number of increasingly-specific searches as I
understand a problem better, and each time the answer that actually guides me
to the next step comes from the same person/place.

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guelo
Click bait

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kebman
Imagine that. Centrifugal force will actually pull the cubes to the side of
the container in an ordered fashion... What a miracle!

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peterburkimsher
Has nobody else noticed the James Bond pun?

[https://en.wikipedia.org/wiki/Shaken,_not_stirred](https://en.wikipedia.org/wiki/Shaken,_not_stirred)

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nyc111
Isn't there also a probabilistic angle? On the second video, on the outer
circle I see that same sides repeat at most 3 times. Can this be a true random
number generator?

Here are the numbers:

1-2-6-4-6-6-6-4-5-3-6-1-2-6-1-2-6-4-6-3-1-1-6-4-3-6-3-2-3-1-3-1-6-3-4-1-4-6-4-3-2-2-4-1-6-1-2-3-4-4-5-5-5-4-1-1-5-4-5-2-6-5-1-1-1-5-4-4-1-1-3-6-6-4-1-4-1-2-4-1-4-6-5-2-1-4-5-1-1-4-1-2-5-3-6-6-3-6-2-5-5-2-3

And here is the distribution:

1 --> 24

2 --> 13

3 --> 13

4 --> 20

5 --> 13

6 --> 20

~~~
nl
By "Ordered" they don't actually mean anything to do with the numbers. It's
unfortunate terminology clashing.

