# 17-sided dice?? **URL:** \ **Category:** The Game Room\ **Created:** [November 7, 2008, 1:31am UTC](https://boards.straightdope.com/t/17-sided-dice/471573 "2008-11-07T01:31:00Z")\ **Posts on this page:** 20\ **Page:** 2
**Author:** ![chrisk](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@chrisk](https://boards.straightdope.com/u/chrisk)\ **Post date:** [November 7, 2008, 4:34pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/21 "2008-11-07T16:34:06Z")
> [@bouv](#): > > Is a d30 a “platonic solid?” I’ve seen them advertised, and I think maybe _once_ I saw a reference to a D30 in some roleplaying book, but that’s about it. > > They look like [this.](http://www.helps4teachers.com/shop/images/30%20sided%20dice.jpg) > > And it seems [Chessex.com](http://www.chessex.com/Dice/Dice_Home.htm) has several other “non-traditional” dice, like a 3, 5, 7, 14, 16, 24, the aforementioned 30, and 34. And 100…but a 100-sided die is just a sphere with numbers on it…you NEVER get it to perfectly have one number facing up. Based on that picture, the d30 is not platonic, since its faces seem to be rhombus-shaped. (And since there is no thirty-sided platonic solid.) ---
**Author:** ![Elendil\_s\_Heir](https://avatars.discourse-cdn.com/v4/letter/e/7cd45c/32.png) [@Elendil\_s\_Heir](https://boards.straightdope.com/u/Elendil_s_Heir)\ **Post date:** [November 7, 2008, 5:00pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/22 "2008-11-07T17:00:36Z")
Our dark lord and master Cthulhu commands us all to use non-Euclidean dice, of course. It’s impossible to figure out what you’ve rolled, and they drive you crazy if you even look at them! Bwahahahahahaha! ---
**Author:** ![glee](https://avatars.discourse-cdn.com/v4/letter/g/b5a626/32.png) [@glee](https://boards.straightdope.com/u/glee)\ **Post date:** [November 7, 2008, 5:56pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/23 "2008-11-07T17:56:21Z")
> [@Ethilrist](#): > > 17-siders are used to randomly determine the age of Minor DNPCs (dependent non-player characters, like Aunt May in Spiderman or Ando in Heroes). But you could easily add three more rolls and use a d20 e.g. rolling an 18-19 = 17 years old; rolling 20 = DM choice. Also there’s quite a difference between a 1 year old and a 16 year old - has the DM prepared for both possibilities? P.S. Hi, What Exit? ---
**Author:** ![JSexton](https://avatars.discourse-cdn.com/v4/letter/j/96bed5/32.png) [@JSexton](https://boards.straightdope.com/u/JSexton)\ **Post date:** [November 7, 2008, 5:59pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/24 "2008-11-07T17:59:47Z")
> [@chrisk](#): > > Which leads naturally to the question - what numbers of faces could a solid be made in with all faces symmetrical - obviously the spindle approach will work for any even number, though a d100 made that way would look pretty weird. What about a d9 or a d15? Could prime numbers ever be made symmetrical this way? Sure. Just imagine a spindle with rectangular faces instead of triangular. True, you’d have an edge facing up instead of a face, but that’s easily solved by marking the numbers into the sides, like a d4. ---
**Author:** ![control-z](https://avatars.discourse-cdn.com/v4/letter/c/eada6e/32.png) [@control-z](https://boards.straightdope.com/u/control-z)\ **Post date:** [November 7, 2008, 6:04pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/25 "2008-11-07T18:04:18Z")
I remember when I first started playing D&D at age 11 or 12, we couldn’t figure out the 4-sided die, so we did something stupid like try to read the left-most number on the side that faced the person who rolled. ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [November 7, 2008, 6:16pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/26 "2008-11-07T18:16:19Z")
> [@Ethilrist](#): > > 17-siders are used to randomly determine the age of Minor DNPCs (dependent non-player characters, like Aunt May in Spiderman or Ando in Heroes). Hmm, in my world, 14 is the age of majority among many social classes. I suppose I could have a noble die, a guilded freeman die, an unguilded freeman die, and a serf die. Of course, if I get pissy enough, they all die! ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 7, 2008, 6:19pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/27 "2008-11-07T18:19:58Z")
Non-symmetric dice like the d5 can never be completely fair: You can empirically get it pretty close to fair, for “normal” rolls, but things like how hard you throw the die and the surface you’re rolling on can cause a bias one way or the other. Thus, for instance, a d5 which is proportioned to roll fair on a wooden tabletop might not roll fair when rolled on a mousepad. The d100 has the same problem, though nobody ever notices it. The d30 isn’t a Platonic solid, but it has exactly the same set of symmetries as a d12 or d20. It bears the same relationship to them as the rhombic dodecahedron bears to the cube and octohedron. For other fair numbers of faces (not counting spindle dice, which you can find for any even number), you can make: d4 d6 d8 At least three different kinds of d12: One with pentagons, one with rhombi, and one with isocoles triangles d20 At least three different kinds of d24: Two with isocoles triangles, and one with kite shapes d30 At least two different kinds of d60, both with isocoles triangles (one obtuse and one acute) d120, with triangular faces of no particular symmetry ---
**Author:** ![Dead\_Cat](https://avatars.discourse-cdn.com/v4/letter/d/9fc29f/32.png) [@Dead\_Cat](https://boards.straightdope.com/u/Dead_Cat)\ **Post date:** [November 7, 2008, 6:24pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/28 "2008-11-07T18:24:04Z")
> [@Dead\_Cat](#): > > I have a game called Card Dice which has supposedly fair 13-sided dice. Actually, I think they were 14-sided, sort of football (as in soccer) shaped, but with all faces the same (not pentagons and hexagons). I’ll see if I can find it over the weekend, but this thread may have died by then (or, more likely, I’ll forget). ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [November 7, 2008, 6:44pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/29 "2008-11-07T18:44:19Z")
> [@chrisk](#): > > Based on that picture, the d30 is not platonic, since its faces seem to be rhombus-shaped. (And since there is no thirty-sided platonic solid.) In the interests of fighting ignorance, the [Platonic solids](http://en.wikipedia.org/wiki/Platonic_solids) are convex regular polyhedrons. There are five and only five such solids: [ul] [li]Tetrahedron - d4[/li][li]Cube - d6[/li][li]Octahedron - d8[/li][li]Dodecahedron - d12[/li][li]Icosahedron - d20[/li][/ul] Dice made in these shapes will be fair but, as previously noted, these are not the only fair shapes. ---
**Author:** ![Giles](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/giles/32/60_2.png) [@Giles](https://boards.straightdope.com/u/Giles)\ **Post date:** [November 7, 2008, 6:49pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/30 "2008-11-07T18:49:41Z")
> [@Chronos](#): > > For other fair numbers of faces (not counting spindle dice, which you can find for any even number) … If by a “spindle dice” you mean a prism with a pyramid on each end, with proportions so that it’s not stable on the triangular faces, but only on the rectangular faces (e.g., a pencil sharpened at each end), why can’t it have any number of faces from three upwards? And so for a d17, you have a solid with 17 rectangular sides (all equal) and 34 triangular sides (also all equal), which won’t come to rest on a triangular side, because it would immediately tip over. ---
**Author:** ![bobthebuilder](https://avatars.discourse-cdn.com/v4/letter/b/c67d28/32.png) [@bobthebuilder](https://boards.straightdope.com/u/bobthebuilder)\ **Post date:** [November 7, 2008, 7:01pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/31 "2008-11-07T19:01:10Z")
kinda off topic but when I was look for free Table Top Role Playing games I found this: [http://legendaryquest.com/](http://legendaryquest.com/) It uses a 30 sided die as the major die of the game. I bought one before I decided that it was too complicated to use as my first RPG. (so now Im using the simplest gaming system in the world: RISUS) ---
**Author:** ![asterion](https://avatars.discourse-cdn.com/v4/letter/a/4da419/32.png) [@asterion](https://boards.straightdope.com/u/asterion)\ **Post date:** [November 7, 2008, 7:26pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/32 "2008-11-07T19:26:57Z")
> [@Terminus\_Est](#): > > I routinely carry around several d2s in my pocket. Though I usually use them to buy things. I learned the hard way that a bunch of gamblers do not like hearing shooting craps referred to as “rolling 2d6.” Then again, it may not have helped that I was betting dark side on a cold table. Serious question: Has anyone ever made a dice gambling game that uses anything besides Xd6? ---
**Author:** ![tdn](https://avatars.discourse-cdn.com/v4/letter/t/94ad74/32.png) [@tdn](https://boards.straightdope.com/u/tdn)\ **Post date:** [November 7, 2008, 7:54pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/33 "2008-11-07T19:54:43Z")
> [@asterion](#): > > Serious question: Has anyone ever made a dice gambling game that uses anything besides Xd6? You’re welcome to play in my craps game that uses 2d20. Warning: The odds favor the house. ---
**Author:** ![Terminus\_Est](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/terminus_est/32/3087_2.png) [@Terminus\_Est](https://boards.straightdope.com/u/Terminus_Est)\ **Post date:** [November 7, 2008, 8:06pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/34 "2008-11-07T20:06:56Z")
> [@asterion](#): > > I learned the hard way that a bunch of gamblers do not like hearing shooting craps referred to as “rolling 2d6.” Then again, it may not have helped that I was betting dark side on a cold table. > > Serious question: Has anyone ever made a dice gambling game that uses anything besides Xd6? There’s this [ancient Roman d20](http://www.christies.com/LotFinder/lot_details.aspx?intObjectID=4205385) that was recently auctioned by Christie’s. It’s unknown what game the die was used for, but it wouldn’t surprise me if it were used for gambling. Some creative Googling has lead me to this column about [Fair Dice](http://www.maa.org/editorial/mathgames/mathgames_05_16_05.html). It suggests that one can make fair dice with sides 2_n_. Aside from the familiar shapes (including d10), the d14, d16, and d24 are also available. You can also get the d3, d5, and d7. [Here’s one site](http://www.g2ch.com/dice-gamescience-dice-c-21_43.html) that sells them. ---
**Author:** ![Chronos](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/chronos/32/134_2.png) [@Chronos](https://boards.straightdope.com/u/Chronos)\ **Post date:** [November 8, 2008, 12:19am UTC](https://boards.straightdope.com/t/17-sided-dice/471573/35 "2008-11-08T00:19:17Z")
Quoth **Giles** : > [@](#): > > If by a “spindle dice” you mean a prism with a pyramid on each end, with proportions so that it’s not stable on the triangular faces, but only on the rectangular faces (e.g., a pencil sharpened at each end), why can’t it have any number of faces from three upwards? Actually, I meant “two pyramids attached base to base, possibly skewed to kite-shaped sides”, like the d10. Strictly speaking, the cube and octohedron also fall into this category, but they’re both more symmetric than that, so deserve special consideration. An end-capped prism or a dreidle can be made for any number of sides, but it feels a little like cheating to me to have sides on the die that it can never land on (or at least, never stay on if it does land on them). ---
**Author:** ![Rich\_Mann](https://avatars.discourse-cdn.com/v4/letter/r/ce73a5/32.png) [@Rich\_Mann](https://boards.straightdope.com/u/Rich_Mann)\ **Post date:** [November 9, 2008, 8:17am UTC](https://boards.straightdope.com/t/17-sided-dice/471573/36 "2008-11-09T08:17:53Z")
So…has anyone besides me ever made any [32-sided](http://ansonartstudio.com/Eric/BuckyDice.html) dice? ---
**Author:** ![chrisk](https://avatars.discourse-cdn.com/v4/letter/c/6de8d8/32.png) [@chrisk](https://boards.straightdope.com/u/chrisk)\ **Post date:** [November 12, 2008, 12:38pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/37 "2008-11-12T12:38:25Z")
> [@Terminus\_Est](#): > > In the interests of fighting ignorance, the [Platonic solids](http://en.wikipedia.org/wiki/Platonic_solids) are convex regular polyhedrons. There are five and only five such solids: > [ul] > [li]Tetrahedron - d4[/li][li]Cube - d6[/li][li]Octahedron - d8[/li][li]Dodecahedron - d12[/li][li]Icosahedron - d20[/li][/ul] > Dice made in these shapes will be fair but, as previously noted, these are not the only fair shapes. Nitpick: Such dice will be geometrically fair, but might still have some trickery built into them, (uneven weighting, certain faces being more adhesive than others etcetera,) that might bias them. I’ve seen a long list of the way that craps dice can be ‘fixed’, and most of them would apply to all other platonic solid dice, or all dice in general, I think. And can a mismarked die, (say, a d6 with sides marked as 4, 5, 6, 4, 5, 6) be considered ‘fair’ if there are no other issues with it? Each side has an equal chance of coming up, but not all of the results expected have any connection with the sides of the die. ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [November 12, 2008, 2:18pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/38 "2008-11-12T14:18:40Z")
> [@chrisk](#): > > And can a mismarked die, (say, a d6 with sides marked as 4, 5, 6, 4, 5, 6) be considered ‘fair’ if there are no other issues with it? Each side has an equal chance of coming up, but not all of the results expected have any connection with the sides of the die. [Sicherman dice](http://en.wikipedia.org/wiki/Sicherman_dice), which will roll 2-12 with the same distribution as regular dice. ---
**Author:** ![Subway\_Prophet](https://avatars.discourse-cdn.com/v4/letter/s/ecb155/32.png) [@Subway\_Prophet](https://boards.straightdope.com/u/Subway_Prophet)\ **Post date:** [November 13, 2008, 8:59pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/39 "2008-11-13T20:59:54Z")
> [@Rich\_Mann](#): > > So…has anyone besides me ever made any [32-sided](http://ansonartstudio.com/Eric/BuckyDice.html) dice? I’ve made non-dice (ornamental) buckyballs before. Lots and lots of tape. I don’t think they’d be fair dice, since the twelve pentagons have lower surface area than the twenty hexagons; your odds of rolling an individual hexagon would be slightly higher than an individual pentagon. Though I’m sure you can fudge around this by rounding off the edges of the hexagons more than the pentagons, it’d be more work than I’d want to do. Me, when I need 1d32, I roll 1d4-1 and 1d8-1 then convert from octal to decimal and add 1. 🙂 ---
**Author:** ![Lumpy](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lumpy/32/446_2.png) [@Lumpy](https://boards.straightdope.com/u/Lumpy)\ **Post date:** [November 14, 2008, 3:03pm UTC](https://boards.straightdope.com/t/17-sided-dice/471573/40 "2008-11-14T15:03:58Z")
Another question: 2D6 (36 combinations) is handy for rolling random alphanumeric characters, but is there any way to mark the dice for a readable result, without having to resort to a lookup table? [Previous page](https://boards.straightdope.com/t/17-sided-dice/471573.md?page=1) [Next page](https://boards.straightdope.com/t/17-sided-dice/471573.md?page=3)