Fair Dice (Part 1) - Numberphile

Probability expert Professor Persi Diaconis (Stanford University) talking about dice.
More links & stuff in full description below ↓↓↓
Part 2: • Fair Dice (Part 2) - N...
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Diaconis/Keller paper on fair dice: bit.ly/FairDicePaper
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[@carpedm9846]

"There are 5 fair dice." *angry d2 noises

[@LannasMissingLink]

*d2 lands on its side

[@The_Murder_Party]

deniz-usta Gedik *angry d20 noises.*

[@theprocastinators9518]

@@The_Murder_Party *Angrily rolls percentile dice*

[@The_Murder_Party]

The Procastinators I mean to be fair percentile are two d10s, but this is fair.

[@draxthemsklonst]

Never had a D2. Is there a die for that? Or is it a coin?

[@z-beeblebrox]

I love this guy's name. It's like the name someone would have in a medieval fantasy story. "Quick, m'lord! We must reach the king's statistician Persi Diaconis before sundown or all hope is lost! He's the only one who knows how to make a fair die out of non-regular polygons!"

[@irisidem6580]

Finally, a name for my NPC wizard.

[@linkmariokirby7373]

It is rumoured that the legendary artificer, Persi Diaconis of the Order of the Logician, once created an object that appeared to be a normal dice. In truth, this dice was filled with magic, and power, and quite a lot of hatred, and its roll would influence the very fate of the world...

[@aurelia8028]

Yeah his name is awesome! :D

[@marksimmons5872]

Be careful not to attack him though, he does 2d10 math damage.

[@berryzhang7263]

It sounds like something out of the game twisted wonderland and I love it

[@klaxoncow]

All a D&D player wants to know is whether the D20 is a fair dice. ;D

[@ukasznosal3657]

That's the regular icosahedron, one of platonic shapes which he described as fairest.

[@KuraIthys]

Yes. I did wonder if the d20 was in the standard platonic solids set... I suppose the most questionable die used in D&D (aside from one for which no dice formally exist, such as d100, or d2) would be the d10. All the others are platonic solids. d4, d6, d8, d12, and d20, and then d10...

[@Vcdomith]

i guess

[@bronzedivision]

It never is...

[@CasMullac]

Wil Wheaton might disagree.

[@Tolop07]

Your channel turned me from a person who thought they hated maths, to someone who appreciates its beauty, thanks!

[@Guru_1092]

I've always appreciated math. Its basically our way of explaining the universe. I'm just absolutely garbage at it, and that makes me bitter.

[@camdix3250]

@@Guru_1092 I know just how you feel. I share that bitterness as well.

[@dolphinboi-playmonsterranc9668]

Fair dice: Not the DM's

[@Watchers_Puppet]

As a Dungeon master I approve this message.

[@wvvwkx]

In high school our physics teacher used to choose people for oral exams by throwing a 30 sided die lol

[@redbeam_]

that sounds so weird and disgusting...

[@natea5225]

redbeam_ why?

[@emersonharris142]

@Nate his mind is in the gutter, "oral exams"

[@natea5225]

Emerson Harris I know. Im just saying that it shouldn't sound dirty and that his mind is in the gutter.

[@OonHan]

is it fair?

[@stevenmartinez1230]

For anyone interested, here are the names of the shapes shown at 7:20 Left to right, then top to bottom; cube/hexahedron, octahedron, pentagonal hexecontahedron, pentagonal icosahedron.

[@tubevolts]

*opens gaming shop called "Die, die, die!"*

[@themobiusfunction]

The missing one is pentakis dodecahedron

[@angerberry]

@AINIEL YABUT the "not sure" shape is actually a rhombic dodecahedron

[@KiryokuYT]

You're a legend. This comment should be pinned.

[@misdelivereddishwasher1011]

The way this man describes dice reinforces the idea that there's a very fine line between insanity and genius.

[@shanedk]

I once saw 7-sided dice, that were basically extruded pentagons. And my initial reaction was that there's no way such a die could be fair, but then I thought about it for a few minutes. If you have a pentagon that's extruded very thinly, like a wafer, then it'll be biased in favor of the two pentagonal faces and the other 5 faces will hardly ever show up. If it's extruded several feet, then the two pentagonal faces will hardly ever show up and you'll usually get one of the 5 others. So there MUST be a sweet spot in the middle where the biases cancel out, and you'll get one of the pentagonal faces 2 out of 7 times!

[@shanedk]

Ah, I see now he covered that in Part 2! Maybe not so fair after all...

[@ArcheoLumiere]

meh, tops are really useful for X sided dice, take the dreidel for example.

[@crackedemerald4930]

INFINET SIDE DIAS!

[@Luigicat11]

It'd just make more sense to have a heptagonal prism and round the edges for a 7-sided die. That's what they did for the 3-sided die.

[@KnakuanaRka]

I think standupmaths (a side channel for Matt Parker) did a video on a similar problem, finding the dimensions that would make a cylinder work as a 3-sided die. I remember that when they were trying to calculate it, they got two different results based on what area was selected for the random distribution, and they tried rolling a bunch of such dice themselves, but I don’t remember if they got any results from that. There were a bunch of people in the comments (including me) who were saying that it would never work due to the fundamental lack of symmetry between the sides of the cylinder. In particular, the way you throw it majorly affects the results; ie, throwing it so it rolls along its axis means that you would get far fewer of the two ends and too many of the band. Essentially, isohedral dice are fair because all the sides are interchangeable. However you throw the die, it can be oriented beforehand so that it has the same overall shape and thus rolls the same way, but any other side you want ends up on top. Because of this, if the original position of the die is random and unknown, so is the resulting roll. This is not true for the cylindrical die; you can’t put the band in the place of one of the ends, or vice versa. So it can never truly be fair. Just use a top for stuff like that, or try cubical dice and count opposite sides the same. PS: speaking of the starting position being unknown, some people there tried to argue that this argument was wrong because ordinary dice can also be affected by the way you throw them. For example, some people have become well-known for cheating at craps via something called the blanket roll; basically, they throw the dice so that they roll around only one axis (similar to what I said about the cylindrical die), and like that, the two sides at the end of the axis (in this case, usually 1 and 6) were less likely to end up on top. My answer to that is that this effect depends on the original position of the die being known; the blanket roller has to look at the dice and put the 1 and 6 where they want them for this to work. If they just grabbed the die and threw it without looking, their chances of getting, say, a 1 wouldn’t be any different from before. Again, this is because the dice’s sides are interchangeable; the cylindrical die’s aren’t, so they can’t be thrown fairly.

[@ChristopherFonseka]

Is it possible to make strategically unfair dice? I've always wanted to make a 12 sided dice, with the same probabilities as two 6 sided die

[@jmiquelmb]

Maybe you could make the faces with the central values larger than the ones with the extreme values? Make 7 huge and 1 and 12 tiny.

[@birdy_coolbeans]

one problem with that is that two 6-sided dice will never land on a sum total of 1.

[@ndrsbrtls]

There are only eleven possible outcomes to a 2D6 throw. ;) Still an interesting question, though.

[@JossLun]

jmiquelmb: I would say the opposite, because big faces are more stable, thus, if 7 is on a small face opposite to 12, probability would be correct.

[@jmiquelmb]

Josselin Luneau If I undertand well, larger faces would mean more probability. Then, 7 should be in the larger one because it's the most probable result, while 2 and 12 (not 1 and 12 like I said incorrectly before) should be on the smaller ones. It's easier to get a central number on a two dice throw because there's more possible combination outcomes (7: 6+1, 2+5, 3+4, 4+3, 5+2, 1+6; 2 and 12: just 1+1 and 6+6)

[@jekyllgaming99]

"Small changes in the initial conditions change what side faces up" In othere words, dice are not just random, but chaotic :D

[@FirstnameLastname-bh9qs]

"There are only five fair dice, d4, d6, d8, d12, and d20" *sweats in white wolf*

[@gillasosaurus]

D10 bruh

[@InfernalBanana]

Wild Magic Sorcerer: *Sweats in D100*

[@williamcole7488]

D10

[@AlexH274]

@@gillasosaurus d10 isn't fair. Vertices of 4 or 5 depending on position.

[@brettonjohansen1619]

@@AlexH274 k, but they're statistically equally likely, which is what matters when it comes to fairness

[@Czeckie]

"Talking to me about dice and fairness is like talking to a California wine person about wine - it can go forever." Please do!!

[@WillReddish]

6:47 I was waiting for him to mention a d10, then he invented it

[@PhilHibbs]

What he described is not a traditional d10, a d10 is a dodecahedron with two faces extruded to points. On a d10, the faces interlock with two opposite faces. His d10 only has one opposite face connected to each.

[@JossLun]

There is one of the interests of simulating chance: once they're balanced, all virtual die are fair.

[@tommy_svk]

So I tried making an actual list of the fair dice as shown at 7:23, using these visuals and the original paper. Here's what I've got: D6 - regular cube D8 - regular octahedron D60 - pentagonal hexecontahedron D24 - pentagonal icositetahedron D60 - pentakis dodecahedron D12 - rhombic dodecahedron D30 - rhombic triacontahedron D24 - triakis octahedron D4 - regular tetrahedron D24 - tetrakis hexahedron D60 - triakis icosahedron D60 - deltoidal hexecontahedron D12 - triakis tetrahedron D24 - deltoidal icositetrahedron The infinite family of bipyramids (pictured is the triagonal bipyramid I believe) D48 - disdakys dodecahedron D120 - disdakys triacontahedron D12 - regular dodecahedron D20 - regular icosahedron After that I am kinda lost. The visuals are confusing me a bit, cause the deltoidal icositetrahedron and disdakys dodecahedron seem to be there twice (at positions 14 and 22 and positions 16 and 21 respectovely). The second to last shape also looks like just a regular octahedron, which is already listed before. The last one also looks like a rhombic dodecahedron, also already listed. Furthermore, after reading the original paper, I've come to understand that the fair dice are: 5 Platonic Solids, 13 duals of Archimedean Solids (known as Catalan Solids) and 2 infinite families. Based on the paper I think the infinite families are supposed to be bipyramids and trapezohedra. But that's all I got and that's just 20 families. The video says there should be 30, but I can't figure out what the remaining solids in the video are supposed to represent and the paper seems to be talking about only 20 families as well, unless I missed something. If anyone has any ideas, please let me know.

[@watchman9198]

My man that was a lot of work

[@irinore]

That d4 awakened a deep anger within me

[@grapefruittango4707]

"I have a thirty sided dice" Who wants to bet that he got it to play D&D

[@Her_Imperious_Condescension]

What TTRPG needs a d30?

[@MrJdsenior]

I will.

[@eddarby469]

Just bought one for my son to use as a DM.

[@daedra40]

This was as mathematically and philosophically as beautiful a video ad any other numberphile video as I've watched ever.

[@Zirkalaritz]

"(...)new Tadashi video soon, that's something to get excited" Oh Brady, you know your audience so well...

[@michael1234252]

4:20 reminds me how a standard 3x3x3 Rubik's cube works. When you make one full turn on one side it stays in the cube shape. But when you change the shape into lets say a Rhombohedron while still keeping the same turning cuts as a standard 3x3x3 Rubik's cube it starts to change shape when mixing it up.

[@Adderkleet]

Great to see Game Science dice in use.

[@attar81]

Zocchi dice!

[@Desmaad]

I'm guessing he chose them because of their purported fairness.

[@gothicsoldier]

I got my game science dice to overcome dice superstition, and have since become superstitious about using any dice that aren't my game science dice

[@allanchampie2872]

Adderkleet that’s what I thought! I saw the clipped corners on the d4.

[@paulcoy9060]

I was hoping he would said something about the sprue discoloration.

[@misterterse94]

Heard him speak in New York a few weeks ago. Really entertaining and insightful speaker.

[@jordiperellogelabert1770]

You're more than welcome Brady! Best channel ever!

[@derbistheeternal2947]

Dammit! I thought this video had the man with a thousand Klein bottles when I saw the thumbhnail but it was an impostor.

[@slep5039]

Right?!?

[@yellowmeerkat97]

Ah, but this is Perci Diaconis, a magician who studied with Dai Vernon. Just as interesting. Problem is, Brady has no reason to ask him about it.

[@neosoul2203]

Cliff Stohlen Identity

[@tafazzi-on-discord]

Make it stop.

[@Awgolas]

Casinos HATE This Man: Find Out Why

[@MrJdsenior]

Yeah, right, because Casinos make so much less money before him than after him. What the heck are you talking about? I'm not sure you know how Casinos work. Either that, or you haven't thought the statement through. The point where the rubber meets the road is the point where the rubber meets the road, and I can prove that mathematically.

[@tommessig2060]

love this! being a gamer i roll dice all the time, so this is a great video.

[@SuperOm1234]

'Fair dice' feels like it should be a saying ...

[@jmiquelmb]

I think what you said is fair dice

[@SuperOm1234]

jmiquelmb haha! yeah, just like that :)

[@B3nnub1rd]

I cannot talk about probability all day like Prof Persi, but I'll watch any Numberphile video, so- fair dice.

[@DioJK]

I think what he said is but a parker square of a fair dice

[@hobbified]

No dice.

[@owdeezstrauz1268]

6:45 did he just say "fivegon"??? 😞

[@NonDelusional74611]

If all the dimples in a golf ball could be numbered, would it be fair??

[@bgbong0]

Only if it were possible to space every dimple evenly apart, and make sure all dimples have the same number of adjacent dimples in a way that is identical and symmetrical to every other dimple. Someone who know more about the design of golf balls could probably say for sure. EDIT: After watching a few videos the best I can really say is; maybe? I'm pretty sure golf balls are carefully designed to meet the right criterion for fairness, because a fair dimple placement is required for aerodynamics, which is the whole reason golf balls have dimples in the first place.

[@edderiofer]

Probably not. If you look closely, you see that some dimples are next to five other dimples, and others are next to 6. This means that the symmetry of a golf ball isn't face-transitive. It could be possible to create a golf ball to be experimentally fair despite this, but why would you want to? Just use a random number generator or something.

[@antoniolucibello233]

Since it's round, it wouldn't stop turning until something stopped it or it finished all the momentum, so it wouldn't land and you wouldn't be able to recognize the face it shows

[@gummipalle]

There are 100 sided dice, they look like golf-balls....

[@KaitouKaiju]

Yes, if it were perfectly spherical and dimpled in such a way where one is directly across from another through the center.

[@Gremlins422]

Thanks for making great videos with smart people Brady! :)

[@DouglasZwick]

Ooooh, he got me all excited at the end there about the next Tadashi video!

[@cpt_nordbart]

what about this dice guy? did he end up with equal results for all 6 sides of a die?

[@turun_ambartanen]

don't think so. they mentioned the weight difference, especially between 1 and 6, shortly after talking baou him. i guess he had less 6s than 1s.

[@BeatlesCuber]

he would of been infinitely close.

[@samshygiene3202]

Pretty sure it would be more 6's. 1 is less material removed therefore heavier and more likely to be on the bottom. The inverse is true for 6.

[@RmonikMusic]

I think you would need an absurd amount of data to notice that difference to be honest.

[@sk8rdman]

Well, he rolled it 3.5 million times, so...

[@adityakhanna113]

Pro-fair-sor Die-cone-is... :)

[@B3nnub1rd]

I'll never forget his name again!

[@drifter23337]

I took discrete probability at SUNY Albany with Professor Martin Hildebrand, whom I think had this Professor Diaconis as his PhD advisor. I imagine this professor has advised many PhD candidates, but Hildebrand seemed to stand out as pretty brilliant (Harvard PhD after all). Any of you guys take classes with Professor Diaconis or any of his "descendants"? I do believe my prof at UAlbany has (obviously) published with Prof Diaconis as well....

[@emmettraymond8058]

Nomen est omen!

[@ozdergekko]

Thanks for legibly showing the complete paper!

[@itchykami]

I love how often I come up with an issue with something someone is saying, and the question is brought up in the video.

[@DannyPhantom288]

Спасибо за видео очень интересно и полезно

[@DrSnap23]

Would a tesseract be a fair die though ? =D

[@andrasfogarasi5014]

A hypercube, yes.

[@31nar288]

Yeah, it would have the same chance to land on all 8 volumes.

[@snigefar]

They have made a video called "Perfect Shapes in Higher Dimensions" that is kind of this problem in higher dimensions.

[@jacksainthill8974]

+31nar288 Correction, all 8 _cubes_. (Nobody says that a 3D die lands on one of its _areas_.) Liked anyway. Cheers ;) [Edited to add] On second thoughts. maybe even _cubes_ isn't right. What (3D) corresponds to 2D _sides_?

[@bgbong0]

You'd have to make sure you were throwing it in 4 dimensional space too, though, since in our 3D space it would only flip in 3 different directions which would make it unfair.

[@danielribastandeitnik9550]

Very interesting! I had the same idea when he showed a dice made from a pentagon.

[@hennadiimadan6993]

Ahhh, procrastination brings me back to my work, AND to E.T. Jaynes's book I'm in the process of reading!

[@the_kraken6549]

*Several D&D players including myself are typing*

[@whatthefunction9140]

is this the klein bottle guys brother?

[@NonTwinBrothers]

Ummm.... no.

[@whatthefunction9140]

Well you username checks out. I trust you.

[@jumpman8282]

Persi Diaconis. Cliff Stoll. Maybe half brothers...

[@ThePCguy17]

It's the same guy, people. Geez, I hope you're all joking...

[@Peglegkickboxer]

this brings back memories of crystallography. Good o'l mineral symmetry groups.

[@Nanninone]

Thanks for the video!

[@jansenart0]

So, the d30 is somewhat similar to a soccer ball, in that it's a shape made of a pattern of two different subshapes, namely 3x5-rhomboids and 5x3-rhomboids, and because of that, some values are more likely to show than others. Now I'm really curious as to the frequency distribution of a d30. If anyone knows where to find that, please drop me a line!

[@RDSk0]

No, the d30 is a rhombic triacontahedron, it's made of one shape - the golden rhombus - and all values are equally likely to appear, assuming the weight is evenly distributed.

[@jansenart0]

@@RDSk0 Yes, it's all one facet shape. No, they're not all as likely to show up because of how they're grouped.

[@PhilBagels]

Actually, all the edges on a rhombic triacontahedron (the 30-sider) are in fact the same. You can map any edge onto any other edge the same way you can for the faces. The fair dice shapes are sometimes called "Catalan Solids" or "Archimedean Duals".

[@DanielFerreira-ez8qd]

I'm 5 years late to warning you not to argue with the old mathematician.

[@PhilBagels]

@@DanielFerreira-ez8qd I'm not arguing. I'm just stating a fact. And why in the world should anyone need to be "warned" not to argue with a mathematician?

[@DanielFerreira-ez8qd]

@@PhilBagels I didn't mean "argue" in the aggressive manner, just that you corrected the math man, which is a humorous thing to do in a scenario where you could be corrected immediately. This ain't one of those obviously, I'm just messing around

[@PhilBagels]

@@DanielFerreira-ez8qd But I'm right,

[@ch4r1z4u0153]

Absolutely fascinating - I'd love to see a big venn diagram of face transitive, edge transitive and vertex transitive solids (maybe I should get to work on it myself...)

[@TheMolt1]

"turning it around three things" I love this guy~

[@cq.cumber_offishial]

4:45 as you can see, there is a small triangle at each corner of the tetrahedron, which means there is a chance, an astronomically small chance, that the die can land exactly on the small triangle.

[@user4241]

Exactly. It's just an unfair 8 sided die.

[@NeuroDrone]

Rolls damage: 40k6

[@davidbeyer7848]

This video is insightful and delightful and I feel smarter having watched it.

[@RobleViejo]

You know he is a genius as he closes his eyes while explaining because he is visualizing it.

[@Skyfighter64]

The long story short is that as long as the individual panels of the polyhedrons are made of "equilateral" shapes (All sides AND angles are the same) then the die should be fair in terms of symmetry.

[@kronologie]

7:20 That audio editing though...

[@skaven969]

Excellent video

[@AmishWaffle88]

never thought i would be this engaged in a video about dice.

[@noredine]

I guess the sphere is the fairest of them all, but then again it can sit in the middle of multiple answers

[@Quantiad]

Make it transparent and have a multi-directional laser in the centre that fires out vertically so you can better see what number it's landed on. Cheap and perfectly safe. Problem solved.

[@jorgebaescaetano5416]

In my opinion its not because the way it rolls. The sphere if you look in terms of phisycs it only rolls at 1 direction, by the other way cubes turns on all directions. I don't know, i'm just giving my thoughts

[@noredine]

now that i think about it , a sphere has only one side...

[@pablogriswold421]

Of course, it depends on the rolling substrate. If it's lumpy, the sphere is super fair (if you've just labeled sections as sides), but as Jorge said, you completely control the one axis of rotation if you roll it on something flat.

[@1ucasvb]

Always a critical failure.

[@TheSLK66]

A fair dice may exist, but a fair throw does not. You could make it very close to a fair throw, but conceptually it's impossible I think.

[@gergo6595]

A fair throw is where you didn't intentionally manipulate the chances. The matter of the dice throwing to get a result from a fix pool that you didn't know before the throw. But, it's needed to make it "unfair" to make it possible to determine a value. In a theoretically perfect world a theoretically "perfect" throw would cause the dice infinitely rolling without stopping, because that perfect you throwed. If not, and we assume that the dice is not mathematically perfect object, it would stand on an edge, like a coin. Throw a coin. Heads or tails, but you throwed so perfectly it didn't lean to either side.

[@valor36az]

What a fantastic abstraction

[@necruo7724]

For an algorythm/symetry nerd like me, this is as entertaining as watching a movie in a cinema for normal people

[@CoolGuy55000]

This is how Cliff Stoll would look and act like if he wasn't constantly high

[@vrabiealexandru2755]

yeah

[@derentius]

I have a D120 I use for D&D random tables, I wonder if that's considered fair

[@B...-B906]

i dont think so. do you use the official PHB? cuz if you do there are only d100 random tables and to trow a fair d100 just use two d10.

[@JustNatax3]

Well you could determine a fair number in 1-120 with 2d10, 1d20 and 1d4. Roll the d4: at [1,2,3] it's up to 1-100 at [4] its 101-120 In case of [1,2,3] simply roll 2d10 to get the digits for a d100 _or_ In case of [4] just roll the d20 for your 101-120

[@eddarby469]

Is there a beholder listed on the table? ... that's not fair!

[@Elkatook666]

to extrapolate the theory, BLOWING on the dice for luck, could influence the outcome of the dice roll ! one side of the die would be warmer than the other, influencing the dynamics of the roll ... great video

[@fimwhisper9970]

One question for this brilliant video: So, I naturally had the question whether the simple differentiation between our symmetry group objects and the "real" platonic solids is simply that for the platonic solids their moments of inertia are the same for all coordinate axis around the center of mass of the object. Our symmetry group object f.e. is shaped such a way, that there is a specific "long" (or "short") axis, which would suggest different moments of inertia for rotation around that axis and in the plane perpendicular to it. That would mean that the object would prefer to rotate either around the axis or perpendicular to it, both making some faces more likely than others. On the other hand, an object with all moments of inertia the same for any rotation around the center of mass would keep its initial rotations and such. No rotation axis would be more likely than another. I don't know all platonic solid's moments of inertia, but I assume due to their high symmetry in vertex, edge and face, that they should have the same moments of inertia. That way, only some dice would be fair in their theoretical way of flying through the air with a given angular momentum. So just maybe that might be another thing to consider. Anyway, I liked the video. Good job :)

[@JonCombo]

0:08 "Tetrahedron" That ones got 8 faces. I had a dice with rounded edges, and it managed to stop on an edge. Only once though.

[@DrIcchan]

Gamescience dice! They're the best.

[@evosevenpm7846]

I thought i recognized those immediately, shame I still don't own a pair.

[@jubuttib]

First thought that popped to mind when the video started. =)

[@ian9372]

I saw a 7-sided die. It was a pentagonal prism, so two sides were pentagons and there were 5 sides that were connecting them. The guy who made it was talking about how if you look at it, the pentagons look so much larger than the smaller connecting sides, and you'd think there was a higher chance of the pentagons landing up, but there actually wasn't. He made bets with people where if it landed on a pentagon, he'd give them one dollar, and if it landed on the others, they'd give him two. Of course, he ended up winning because it was a fair die.

[@jfridy]

Fun bit! The dice they are tossing in the examples, the ones with no paint in the numbers and very sharp edges? Those are from Gamescience, a company that prides itself on making them that way because the rounding of the edges can cause flaws with their balance and make them less random.

[@jeshudastidar]

Have an awesome day everyone! :)

[@luizpaulo6535]

no

[@FocusMrbjarke]

I am in pain

[@jackmiak5386]

+NonTwinBrothers im also sick....:(

[@Twitchi]

you to buddy :D

[@gabelance1]

Don't tell me what to do.

[@StefanReich]

The casino dice are pretty

[@elemenopi9239]

I want some. Maybe I’ll get some on amazon tomorrow.

[@lucabozza1750]

The gamescience dice made the video so much better

[@mertonhirsch4734]

you can create fair dice that have symmetrical edges, vertices and sides IF you allow the faces to have even a tiny amount of curvature. For example a toblerone that doesn't have flat ends, but points.

[@JiyakuBuraku]

Rohan is really suspicious of dice now

[@lilysdong1457]

Goddamit, is this a jojo reference?

[@filipsantek1336]

@@lilysdong1457 xD yes, yes it is, and I hate how it got even here

[@13thBear]

If you worry about the fairness of dice, you are either a math professor or a munchkin.

[@Guru_1092]

Or a D&D nerd.

[@tomfieselmann5906]

Hahahaha! "Caught me there... Let me AMEND the statement of my theorem...." - Love it...

[@veggiet2009]

Yayy! Dice Videos!

[@bobsaggat]

old news to every dungeons and dragons player lol

[@Johan-st4rv]

How do you roll a die 3500000 times?

[@ffggddss]

You build a machine to do it, with maybe 20 or 50 dice being tossed at a time, incorporating a camera to record them after each toss, and recognition software to count each outcome from each die, at each toss. At the beginning of Part 2 he shows how a student did this as a project; he used 12 dice at a time. Or you vedge out with dice while watching TV for 15 years.

[@amanitamuscaria6865]

how long have you been on youtube

[@biggawinnacrapsa3870]

You roll it once, then you wait until it comes to rest, then you pick it up and do it again. Do that over and over until you reach the number you are after. I hope this helps.

[@tubevolts]

Your watch as much content as a typical 12-year-old and spend that time rolling, rolling, rolling.

[@y.z.6517]

Rolling a dice every 3 seconds. No resting. No sleeping. That's about a year.

[@overlordinquisitor6565]

Everyone: Goes nuts because of not-cube dice. Dungeons and Dragons players: First time?

[@abhishekkhetan]

Now this is helluva interesting!

[@niteexplorer9934]

SO HOW CAN I WIN A THE CASINO

[@nullpoint3346]

Don't play.

[@Xormac2]

own a casino

[@nullpoint3346]

@@Xormac2 That also works.

[@biggawinnacrapsa3870]

You can start by proofreading your comments before posting, so that you don't come off sounding like an ignorant moron. Morons don't fare too well in casinos. Next, go to videos by 'Dangerous Arm Craps' and watch and listen. Then put it all, everything you've got, across the numbers as soon as you get the dice and don't work them on the Come Out roll. Hit 4 numbers and pull the bets down. Send what you came with home and play only with the profit. You're welcome.

[@juancgonzalez2102]

The best way to win the game is to not play

[@Zaurthur]

only five in the 3rd dimension!

[@blue_tetris]

I'm interested in what types of polychoron dice would be fair, assuming a 4-dimensional space.

[@Zaurthur]

The same ones. and the hyper diamond.

[@robo3007]

There's two more (the triangular and pentagonal bipyramid) plus several other if you allow using non-regular faces.

[@nullpoint3346]

@@robo3007 Regulars only, sorry.

[@connorking8503]

There's only three in 4d. One, Infinity, five, three, three, three...

[@markmandel6487]

For gaming, if not geometry, you can have fair dice of ANY value. Make them in the shape of a prism with that many sides, and sharpen the ends to points or round them off, so the die won't land on an end and stop there. To help you visualize it, a regular everyday pencil, if not cylindrical, is a six-sided prism. Sharpen both ends and you've got a prismatic d6. And obviously these can be made with ANY number of sides greater than 2.

[@brokenwave6125]

Spheres are fair too. Infinite sides. Equally chance on any side facing up. Also, any cylinder based dice that you roll are fair.

[@chaotickreg7024]

Give the sphere dice (a d^3 if you will) a UV texture or color ramp, that way you can extract an X and Y dice value out of every roll.

[@JustVaza]

why am I still watching this at 1 am?

[@Ghork1]

It really bugs me that his 4 sided die have the corners shaved off !

[@hyrekandragon2665]

Have you ever tired rolling a tetrahedron. The corners are very sharp abd make jt hard to pick up. Shavjng them off makings the die more weildy.

[@Ghork1]

lots of time i'm an avid pen and paper player, playing pathfinder mostly now

[@rebeltinaschannel6240]

That's to keep it from hurting when you step on it. Dice roll off the table more often than you think.

[@Science__Politics]

I just thought of a way of finding the "most" fair dice of any number. You must start with a perfect sphere and cut it the minimal number of times to have the desired number of sides, and so that each side is equal in shape & size, whilst retaining as much volume of the original sphere as possible.

[@raiserofchickens]

I bought a set of 'Rogue' dice where the d6 were in a poison bottle design. I quickly discovered that I could better control the outcome by how I released them from my hands when rolling.

[@ixchel3330]

That's the most rouge thing i can think of.

[@KnakuanaRka]

At the start, those 5 shapes would be called Platonian solids, technically speaking.

[@ffggddss]

Yes, but it's, "Platonic."

[@KnakuanaRka]

ffggddss Close enough.

[@wrecksvid]

D2 = a coin

[@steampunkastronaut7081]

Wrong.

[@JanuszGamerX]

lol no

[@DrDress]

Once again top notche graphics

[@donaldasayers]

6:00 The edges on a rhombic triacontahedron ARE transitive. See Wiki on the triacontahedron

[@whoeveriam0iam14222]

it looks weird that his eyes seem constantly closed

[@S1nwar]

old people HAHAHA

[@-morrow]

he's trying to image the geometrical shapes he's talking about, makes stuff easier for some people ;)

[@NormalGayBro]

Just like Brock.

[@LonkinPork]

Any nerd could have told you what those original five dice are: D4, D6, D8, D12, and D20

[@StUCaboose]

As an RPG dice goblin, words cannot express how utterly stressed out 2:30 made me

[@categorygrp]

More videos on group theory, please ^.^

[@needlessToo]

Poor kids, hahaha.

[@BlueEyesWhiteBoy]

You lost me at dice.

[@oldmannaynay]

What about a case for the three sided die... you can see three sided dice shapes within the old pieces for risk which symbolized 10 men. The 1 man pieces were squares, and the 10 man pieces aka cannons were the shape of what seemed a fair three sided dice.

[@ayeariola]

A bicone (two cones connected by their circles) would be also a fair die because the two contact regions (nappe segments) are the same shape.