It had never occurred to me that somebody needed to invent polyhedral dice. There must be so many inventions in the world that I’m completely unaware that there was a point in time before which something didn’t exist and after that it did, thanks to somebody.

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gus_massa 2 days ago | parent | next [-]

There are only 5 Platonic Solids https://en.wikipedia.org/wiki/Platonic_solid : D4, D6, D8, D12 and D20.

There are 13 more solids with equal faces and vertex (but not equal edges) https://en.wikipedia.org/wiki/Catalan_solid but none of them has 100 faces (It looks like a nice project for 3D printing.)

You can cut the corners, but now the faces are different and ensuring all the faces have the same probability is a nightmare. Some info in https://en.wikipedia.org/wiki/Truncation_(geometry)#Uniform_... (This include the soccer ball.) (I have no idea if this include the D100.)

You also can "cheat" and use https://en.wikipedia.org/wiki/Teetotum that allows any number if you don't care too much about the polyhedral property.

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vikingerik 2 days ago | parent | next [-]

The Zocchi d100 isn't face-symmetric and thus isn't a fair die. It's as close as he could get. It's really effectively a golf ball with 100 dimples, but they aren't and can't be arranged perfectly symmetrically.

Any even number dX can be made as a fair die as a bipyramid or trapezohedron. https://en.wikipedia.org/wiki/Trapezohedron These would be the only fair face-symmetric d100s. The standard d10 is this, and you sometimes see a d14 or d18 or something like that constructed this way. It becomes impractical with very thin faces past 20 or so. An odd-numbered fair die is also possible by using one twice as big and duplicating the numbers (like 1-5 twice on a d10.)

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1313ed01 2 days ago | parent | prev [-]

Martin Gardner wrote an article on platonic solids in Scientific American, December 1958, and mentioned this in passing: "All five Platonic solids have been used as dice. Next to the cube the octahedron seems to have been the most popular". I have no idea what games using 8-sided dice were somewhat popular (or existed at all) in 1958 or earlier? I wondered about that since I first read that article some decade ago.

I also read a book about games from ca 1880 and it described 12-sided dice (the usual one, numbered 1-12) as if that was a thing some people used for playing games, but none of the games described in that book used them and I also have no idea about other old games using 12-sided dice.

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bombcar 2 days ago | parent [-]

I've seen some octahedrons but they pale in comparison to the six siders - I suspect partially because it's hard to see an octahedron and assume it's fair. It looks like a parallelogram.

Besides gambling games most dice in antiquity were used in rituals or soothsaying.

	▲	gus_massa 2 days ago \| parent [-]
		Slightly related: In a stone shop nearby my home they sell a nice set of Platonic Solids made of semitransparent stones, but the octahedron is an irregular one :((( It's very similar to the ser in this photo https://www.mercadolibre.com.ar/solidos-platonicos-geometria... It's a nice present for a friend that is a mathematician too, but there is high chance that they will notice.

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amiga386 2 days ago | parent | prev | next [-]

I too would question the term "inventor" here.

* dice: exist for thousands of years

* me: what if these had 100 sides?

* d100: *invented*

A better term would be "creator", because actually creating a 100-sided die that that rolls nicely and each face being equally likely is a lot more difficult than imagining one.

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literalAardvark 2 days ago | parent | prev [-]

Everything you've ever seen that isn't sky, water, air, ground, life was invented by someone.

Heck, many specimens of the last two are inventions, that are insignificant as a % of species but are in the worldwide top by biomass.

It's quite difficult to leave the anthroposphere in much of the world.