Fair Dice (Part 1) - Numberphile

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  • Опубликовано: 11 июл 2024
  • Probability expert Professor Persi Diaconis (Stanford University) talking about dice.
    More links & stuff in full description below ↓↓↓
    Part 2: • Fair Dice (Part 2) - N...
    Tadashi and Dice: • The Most Powerful Dice...
    More dice videos: bit.ly/Dice_Videos
    More Persi Diaconi videos: bit.ly/Persi_Videos
    Diaconis/Keller paper on fair dice: bit.ly/FairDicePaper
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Комментарии • 996

  • @z-beeblebrox
    @z-beeblebrox 7 лет назад +683

    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
      @irisidem6580 5 лет назад +40

      Finally, a name for my NPC wizard.

    • @linkmariokirby7373
      @linkmariokirby7373 4 года назад +20

      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
      @aurelia8028 4 года назад +3

      Yeah his name is awesome! :D

    • @marksimmons5872
      @marksimmons5872 2 года назад +2

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

    • @berryzhang7263
      @berryzhang7263 Год назад

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

  • @Tolop07
    @Tolop07 7 лет назад +238

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

    • @Guru_1092
      @Guru_1092 5 лет назад +16

      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
      @camdix3250 Год назад

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

  • @carpedm9846
    @carpedm9846 4 года назад +1116

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

    • @LannasMissingLink
      @LannasMissingLink 4 года назад +157

      *d2 lands on its side

    • @The_Murder_Party
      @The_Murder_Party 4 года назад +33

      deniz-usta Gedik *angry d20 noises.*

    • @theprocastinators9518
      @theprocastinators9518 4 года назад +45

      @@The_Murder_Party *Angrily rolls percentile dice*

    • @The_Murder_Party
      @The_Murder_Party 4 года назад +26

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

    • @draxthemsklonst
      @draxthemsklonst 4 года назад +12

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

  • @klaxoncow
    @klaxoncow 7 лет назад +2597

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

    • @ukasznosal3657
      @ukasznosal3657 7 лет назад +481

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

    • @KuraIthys
      @KuraIthys 7 лет назад +169

      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
      @Vcdomith 7 лет назад +7

      i guess

    • @bronzedivision
      @bronzedivision 7 лет назад +25

      It never is...

    • @CasMullac
      @CasMullac 7 лет назад +82

      Wil Wheaton might disagree.

  • @dolphinboi-playmonsterranc9668
    @dolphinboi-playmonsterranc9668 5 лет назад +322

    Fair dice: Not the DM's

    • @Watchers_Puppet
      @Watchers_Puppet 4 года назад +15

      As a Dungeon master I approve this message.

  • @wvvwkx
    @wvvwkx 7 лет назад +651

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

    • @redbeam_
      @redbeam_ 7 лет назад +73

      that sounds so weird and disgusting...

    • @natea5225
      @natea5225 6 лет назад +27

      redbeam_ why?

    • @emersonharris142
      @emersonharris142 6 лет назад +94

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

    • @natea5225
      @natea5225 6 лет назад +28

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

    • @OonHan
      @OonHan 6 лет назад +6

      is it fair?

  • @shanedk
    @shanedk 7 лет назад +285

    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
      @shanedk 7 лет назад +47

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

    • @ArcheoLumiere
      @ArcheoLumiere 7 лет назад +22

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

    • @crackedemerald4930
      @crackedemerald4930 6 лет назад +2

      INFINET SIDE DIAS!

    • @Luigicat11
      @Luigicat11 5 лет назад +8

      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
      @KnakuanaRka 5 лет назад +7

      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.

  • @misdelivereddishwasher1011
    @misdelivereddishwasher1011 5 лет назад +16

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

  • @stevenmartinez1230
    @stevenmartinez1230 7 лет назад +53

    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
      @tubevolts 5 лет назад +4

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

    • @themobiusfunction
      @themobiusfunction 2 года назад +2

      The missing one is pentakis dodecahedron

    • @angerberry
      @angerberry Год назад +1

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

    • @KiryokuYT
      @KiryokuYT Месяц назад

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

  • @jekyllgaming99
    @jekyllgaming99 7 лет назад +13

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

  • @ChristopherFonseka
    @ChristopherFonseka 7 лет назад +362

    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
      @jmiquelmb 7 лет назад +56

      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
      @birdy_coolbeans 7 лет назад +143

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

    • @ndrsbrtls
      @ndrsbrtls 7 лет назад +86

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

    • @JossLun
      @JossLun 7 лет назад +15

      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
      @jmiquelmb 7 лет назад +3

      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)

  • @FirstnameLastname-bh9qs
    @FirstnameLastname-bh9qs 4 года назад +80

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

    • @gillasosaurus
      @gillasosaurus 4 года назад +5

      D10 bruh

    • @InfernalBanana
      @InfernalBanana 4 года назад +11

      Wild Magic Sorcerer: *Sweats in D100*

    • @williamcole7488
      @williamcole7488 4 года назад +2

      D10

    • @AlexH274
      @AlexH274 3 года назад +1

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

    • @brettonjohansen1619
      @brettonjohansen1619 3 года назад +2

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

  • @Czeckie
    @Czeckie 7 лет назад +19

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

  • @daedra40
    @daedra40 7 лет назад +3

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

  • @irinore
    @irinore 4 года назад +25

    That d4 awakened a deep anger within me

  • @WillReddish
    @WillReddish 7 лет назад +45

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

    • @PhilHibbs
      @PhilHibbs 7 лет назад +9

      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.

  • @Zirkalaritz
    @Zirkalaritz 7 лет назад +13

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

  • @michael1234252
    @michael1234252 5 лет назад +5

    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.

  • @grapefruittango4707
    @grapefruittango4707 7 лет назад +16

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

  • @tommy_svk
    @tommy_svk 3 года назад +9

    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
      @watchman9198 11 месяцев назад

      My man that was a lot of work

  • @JossLun
    @JossLun 7 лет назад +13

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

  • @tommessig2060
    @tommessig2060 7 лет назад +15

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

  • @misterterse94
    @misterterse94 7 лет назад

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

  • @jordiperellogelabert1770
    @jordiperellogelabert1770 7 лет назад

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

  • @owdeezstrauz1268
    @owdeezstrauz1268 4 года назад +9

    6:45 did he just say "fivegon"??? 😞

  • @SuperOm1234
    @SuperOm1234 7 лет назад +154

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

    • @jmiquelmb
      @jmiquelmb 7 лет назад +46

      I think what you said is fair dice

    • @SuperOm1234
      @SuperOm1234 7 лет назад +4

      jmiquelmb
      haha! yeah, just like that :)

    • @B3nnub1rd
      @B3nnub1rd 7 лет назад +2

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

    • @DioJK
      @DioJK 7 лет назад +1

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

    • @hobbified
      @hobbified 7 лет назад +1

      No dice.

  • @DouglasZwick
    @DouglasZwick 7 лет назад

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

  • @Gremlins422
    @Gremlins422 7 лет назад +2

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

  • @derbistheeternal2947
    @derbistheeternal2947 7 лет назад +122

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

    • @slep5039
      @slep5039 7 лет назад +1

      Right?!?

    • @yellowmeerkat97
      @yellowmeerkat97 7 лет назад +9

      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
      @neosoul2203 7 лет назад +18

      Cliff Stohlen Identity

    • @tafazzi-on-discord
      @tafazzi-on-discord 3 года назад

      Make it stop.

  • @Adderkleet
    @Adderkleet 7 лет назад +49

    Great to see Game Science dice in use.

    • @attar81
      @attar81 7 лет назад +1

      Zocchi dice!

    • @Desmaad
      @Desmaad 7 лет назад

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

    • @gothicsoldier
      @gothicsoldier 7 лет назад +8

      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
      @allanchampie2872 5 лет назад

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

    • @paulcoy9060
      @paulcoy9060 5 лет назад

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

  • @tomfieselmann5906
    @tomfieselmann5906 5 лет назад +2

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

  • @itchykami
    @itchykami 7 лет назад

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

  • @adityakhanna113
    @adityakhanna113 7 лет назад +108

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

    • @B3nnub1rd
      @B3nnub1rd 7 лет назад +4

      I'll never forget his name again!

    • @drifter23337
      @drifter23337 7 лет назад +4

      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
      @emmettraymond8058 5 лет назад

      Nomen est omen!

  • @NonDelusional74611
    @NonDelusional74611 7 лет назад +95

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

    • @bgbong0
      @bgbong0 7 лет назад +23

      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
      @edderiofer 7 лет назад +15

      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
      @antoniolucibello233 7 лет назад +1

      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
      @gummipalle 7 лет назад +16

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

    • @KaitouKaiju
      @KaitouKaiju 6 лет назад +1

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

  • @skaven969
    @skaven969 5 лет назад

    Excellent video

  • @hennadiimadan6993
    @hennadiimadan6993 6 лет назад

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

  • @cpt_nordbart
    @cpt_nordbart 7 лет назад +62

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

    • @turun_ambartanen
      @turun_ambartanen 7 лет назад +6

      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
      @BeatlesCuber 7 лет назад

      he would of been infinitely close.

    • @samshygiene3202
      @samshygiene3202 7 лет назад +40

      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
      @RmonikMusic 7 лет назад +5

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

    • @sk8rdman
      @sk8rdman 7 лет назад +19

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

  • @Awgolas
    @Awgolas 5 лет назад +105

    Casinos HATE This Man: Find Out Why

    • @MrJdsenior
      @MrJdsenior 3 года назад

      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.

  • @ozdergekko
    @ozdergekko 7 лет назад

    Thanks for legibly showing the complete paper!

  • @MoltandMigrate
    @MoltandMigrate 7 лет назад +1

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

  • @donaldasayers
    @donaldasayers 5 лет назад +3

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

  • @DannyPhantom288
    @DannyPhantom288 3 года назад +4

    Спасибо за видео очень интересно и полезно

  • @Nanninone
    @Nanninone 7 лет назад

    Thanks for the video!

  • @danielribastandeitnik9550
    @danielribastandeitnik9550 7 лет назад +1

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

  • @jansenart0
    @jansenart0 3 года назад +5

    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
      @RDSk0 2 года назад +2

      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
      @jansenart0 2 года назад

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

  • @whatthefunction9140
    @whatthefunction9140 7 лет назад +95

    is this the klein bottle guys brother?

    • @NonTwinBrothers
      @NonTwinBrothers 7 лет назад +13

      Ummm.... no.

    • @whatthefunction9140
      @whatthefunction9140 7 лет назад +53

      Well you username checks out. I trust you.

    • @jumpman8282
      @jumpman8282 7 лет назад +8

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

    • @ThePCguy17
      @ThePCguy17 6 лет назад +1

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

  • @AmishWaffle88
    @AmishWaffle88 7 лет назад

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

  • @valor36az
    @valor36az 4 года назад

    What a fantastic abstraction

  • @DrSnap23
    @DrSnap23 7 лет назад +167

    Would a tesseract be a fair die though ? =D

    • @andrasfogarasi5014
      @andrasfogarasi5014 7 лет назад +37

      A hypercube, yes.

    • @31nar288
      @31nar288 7 лет назад +64

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

    • @snigefar
      @snigefar 7 лет назад +14

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

    • @jacksainthill8974
      @jacksainthill8974 7 лет назад +25

      +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
      @bgbong0 7 лет назад +15

      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.

  • @kronologie
    @kronologie 7 лет назад +5

    7:20 That audio editing though...

  • @davidbeyer7848
    @davidbeyer7848 4 года назад

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

  • @Peglegkickboxer
    @Peglegkickboxer 7 лет назад +4

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

  • @DorthLous
    @DorthLous 7 лет назад +10

    "same specific gravity"... Oh boy.

  • @PhilBagels
    @PhilBagels 7 лет назад +3

    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
      @DanielFerreira-ez8qd 2 года назад

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

    • @PhilBagels
      @PhilBagels 2 года назад +1

      @@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
      @DanielFerreira-ez8qd 2 года назад

      @@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
      @PhilBagels 2 года назад +1

      @@DanielFerreira-ez8qd But I'm right,

  • @RobleViejo
    @RobleViejo 4 года назад

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

  • @veggiet2009
    @veggiet2009 7 лет назад

    Yayy! Dice Videos!

  • @noredine
    @noredine 7 лет назад +22

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

    • @Quantiad
      @Quantiad 7 лет назад +2

      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
      @jorgebaescaetano5416 7 лет назад +2

      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
      @noredine 7 лет назад +1

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

    • @pablogriswold421
      @pablogriswold421 7 лет назад +1

      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
      @1ucasvb 7 лет назад +2

      Always a critical failure.

  • @NeuroDrone
    @NeuroDrone 7 лет назад +7

    Rolls damage: 40k6

  • @ch4r1z4u0153
    @ch4r1z4u0153 7 лет назад +1

    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...)

  • @abhishekkhetan
    @abhishekkhetan 7 лет назад

    Now this is helluva interesting!

  • @the_kraken6549
    @the_kraken6549 4 года назад +50

    *Several D&D players including myself are typing*

  • @derentius
    @derentius 5 лет назад +9

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

    • @B...-B906
      @B...-B906 5 лет назад +2

      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
      @JustNatax3 5 лет назад

      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
      @eddarby469 2 года назад

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

  • @lucabozza1750
    @lucabozza1750 4 года назад

    The gamescience dice made the video so much better

  • @gimmeumoney
    @gimmeumoney 7 лет назад +1

    Wasn't anyone else blown away when he said a guy roled a dice 3,500,000 times and recorded the results?!?!

  • @TheSLK66
    @TheSLK66 7 лет назад +21

    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
      @gergo6595 3 года назад +4

      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.

  • @cq.cumber_offishial
    @cq.cumber_offishial 4 года назад +3

    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
      @user4241 2 года назад

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

  • @leungclj
    @leungclj 7 лет назад +1

    dude, i will allow this guy to go on forever. For once, i feel like i understood the whole video.

  • @DrDress
    @DrDress 7 лет назад

    Once again top notche graphics

  • @CoolGuy55000
    @CoolGuy55000 7 лет назад +29

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

  • @Skyfighter64
    @Skyfighter64 5 лет назад +4

    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.

  • @necruo7724
    @necruo7724 4 года назад +1

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

  • @jopaki
    @jopaki 7 лет назад

    Awesome.

  • @JiyakuBuraku
    @JiyakuBuraku 7 лет назад +22

    Rohan is really suspicious of dice now

    • @lilysdong1457
      @lilysdong1457 5 лет назад +1

      Goddamit, is this a jojo reference?

    • @filipsantek1336
      @filipsantek1336 5 лет назад +2

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

  • @DrIcchan
    @DrIcchan 7 лет назад +10

    Gamescience dice! They're the best.

    • @evosevenpm7846
      @evosevenpm7846 7 лет назад

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

    • @jubuttib
      @jubuttib 5 лет назад

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

  • @Vodboi
    @Vodboi 7 лет назад

    You have made another video called "Wierd But Fair Dice". Is the die in that video the one at 7:24 in the 7th collumn, 3rd row?

  • @jfridy
    @jfridy 4 года назад

    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.

  • @StefanReich
    @StefanReich 6 лет назад +6

    The casino dice are pretty

    • @elemenopi9239
      @elemenopi9239 5 лет назад +1

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

  • @JonCombo
    @JonCombo 5 лет назад +3

    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.

  • @ian9372
    @ian9372 7 лет назад +1

    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.

  • @AymaneAbaich
    @AymaneAbaich 7 лет назад

    Last week's guy still my favorite

  • @jeshudastidar
    @jeshudastidar 7 лет назад +48

    Have an awesome day everyone! :)

  • @Johan-st4rv
    @Johan-st4rv 7 лет назад +8

    How do you roll a die 3500000 times?

    • @ffggddss
      @ffggddss 6 лет назад +7

      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
      @amanitamuscaria6865 6 лет назад

      how long have you been on youtube

    • @biggawinnacrapsa3870
      @biggawinnacrapsa3870 5 лет назад +11

      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
      @tubevolts 5 лет назад

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

    • @y.z.6517
      @y.z.6517 5 лет назад

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

  • @Elkatook666
    @Elkatook666 3 года назад

    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

  • @noel_21
    @noel_21 5 лет назад +1

    What about if you consider the fourth dimension? Would they still be perfect dice?

  • @13thBear
    @13thBear 5 лет назад +5

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

  • @niteexplorer9934
    @niteexplorer9934 7 лет назад +7

    SO HOW CAN I WIN A THE CASINO

    • @nullpoint3346
      @nullpoint3346 5 лет назад +14

      Don't play.

    • @Xormac2
      @Xormac2 5 лет назад +4

      own a casino

    • @nullpoint3346
      @nullpoint3346 5 лет назад +2

      @@Xormac2
      That also works.

    • @biggawinnacrapsa3870
      @biggawinnacrapsa3870 5 лет назад

      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
      @juancgonzalez2102 5 лет назад

      The best way to win the game is to not play

  • @categorygrp
    @categorygrp 7 лет назад +1

    More videos on group theory, please ^.^

  • @raiserofchickens
    @raiserofchickens 3 года назад

    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
      @ixchel3330 2 года назад +1

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

  • @JustVaza
    @JustVaza 7 лет назад +4

    why am I still watching this at 1 am?

  • @bobsaggat
    @bobsaggat 7 лет назад +20

    old news to every dungeons and dragons player lol

  • @mertonhirsch4734
    @mertonhirsch4734 7 лет назад

    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.

  • @overlordinquisitor6565
    @overlordinquisitor6565 4 года назад +1

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

  • @Zaurthur
    @Zaurthur 7 лет назад +9

    only five in the 3rd dimension!

    • @blue_tetris
      @blue_tetris 7 лет назад

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

    • @Zaurthur
      @Zaurthur 7 лет назад +1

      The same ones. and the hyper diamond.

    • @robo3007
      @robo3007 7 лет назад +1

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

    • @nullpoint3346
      @nullpoint3346 5 лет назад

      @@robo3007
      Regulars only, sorry.

    • @connorking8503
      @connorking8503 5 лет назад

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

  • @Ghork1
    @Ghork1 7 лет назад +5

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

    • @hyrekandragon2665
      @hyrekandragon2665 7 лет назад +1

      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
      @Ghork1 7 лет назад

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

    • @rebeltinaschannel6240
      @rebeltinaschannel6240 6 лет назад

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

  • @TheMohawkNinja
    @TheMohawkNinja 7 лет назад

    The DnD nerd in me is very much enjoying this video.

  • @skippy9214
    @skippy9214 4 года назад +1

    Talks about the icosahedron, me: “I think you mean a d20”

  • @whoeveriam0iam14222
    @whoeveriam0iam14222 7 лет назад +8

    it looks weird that his eyes seem constantly closed

    • @S1nwar
      @S1nwar 7 лет назад

      old people HAHAHA

    • @-morrow
      @-morrow 7 лет назад +7

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

    • @NormalGayBro
      @NormalGayBro 6 лет назад +1

      Just like Brock.

  • @wrecksvid
    @wrecksvid 5 лет назад +15

    D2 = a coin

  • @oldmannaynay
    @oldmannaynay 2 года назад +1

    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.

  • @fimwhisper9970
    @fimwhisper9970 7 лет назад

    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 :)