# \[Roman\] Dodecahedrons **URL:** \ **Category:** Factual Questions\ **Created:** [February 27, 2023, 9:46pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459 "2023-02-27T21:46:54Z")\ **Posts on this page:** 20\ **Page:** 6
**Author:** ![markn\_1](https://avatars.discourse-cdn.com/v4/letter/m/f9ae1b/32.png) [@markn\_1](https://boards.straightdope.com/u/markn_1)\ **Post date:** [March 20, 2023, 12:10am UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/101 "2023-03-20T00:10:22Z")
If they were cast, the holes (or at least one of them) would have to be part of the casting, not cut out later. I think it would be impossible to cast a hollow object with no holes in it. ---
**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:** [March 20, 2023, 12:21am UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/102 "2023-03-20T00:21:22Z")
The bronze is cast. But it was probably cast using lost wax, so the wax had to be shaped somehow. So you cut out the wax pentagons with a cookie-cutter template, make the holes the appropriate sizes, seal them together into a dodecahedron and attach the knobs, and then cast the bronze from that. ---
**Author:** ![Crafter\_Man](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/crafter_man/32/458_2.png) [@Crafter\_Man](https://boards.straightdope.com/u/Crafter_Man)\ **Post date:** [March 20, 2023, 12:35am UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/103 "2023-03-20T00:35:09Z")
Something to keep in mind is that making one of these things took a lot of time, and required a high level of skill. Very expensive, no doubt. That’s why I think it’s not simply a measurement device; a much simpler & cheaper tool could be made to measure the diameters of coins, for example. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [March 20, 2023, 7:56am UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/104 "2023-03-20T07:56:21Z")
> [@Chronos](#): > > Even just “requires a basic level of competently knowing what one’s doing”, though, I think might price these things out of the knickknack level. The Romans used intricately-shaped bronze items for lots of trivial functions. Those lamps, the fibula I mentioned, these were not expensive rare items, they were common artefacts. Not the cheapest mass-produced junk, mind you - a _cheap_ lamp would be clay, a _cheap_ cloakpin just a straight iron pin. But not high-end, either. Middle-class goods, basically. I certainly don’t think these dodecahedra are mere knick-knacks. I think they had some significance to their owners. > [@Chronos](#): > > And I still think there has to be some reason for the holes to all be different sizes.[…snip…] > that there was some practical task that called for a thing with holes of specific sizes, Whatever that reason is, it would have to account for why there’s no consistent sizing. One of the “it’s a rangefinder” [papers](https://arxiv.org/ftp/arxiv/papers/1206/1206.0946.pdf) has some sample hole sizes. You’ll even see some opposite pairs are the same, or very close to the same, size. And there’s a wide variance in ratios _and_ absolute sizes. > [@Crafter\_Man](#): > > I noticed many of them have two or three grooves around each hole. Others, however, do not - they have dot-circles in a ring/at the corners. Like the top example in the photo **Walken\_After\_Midnight** posted. So if a particular tool made the grooves, why use a different one for the holes in that one? And why what looks like different spacings of grooves for each hole? Also, cutting holes in wax isn’t hard, and doesn’t require a dedicated tool. Just a knife will do (as Mangetout showed) But if you _do_ use a dedicated tool, it’s just a circle cutter, kind of like a small cookie cutter or punch. That doesn’t leave grooves. > [@Chronos](#): > > If they do all have the same arrangement of sizes They definitely don’t. > [@Crafter\_Man](#): > > Something to keep in mind is that making one of these things took a lot of time, and required a high level of skill. A _lot_ of time and _high_ degree of skill? It’s all straight lines and circles. No intricate sculpting. Lost wax bronzework isn’t some lost craft. People still do that kind of work today. Yes, they’re skilled craftsmen, but nevertheless ordinary artisans. _Teens_ can do it… Here, look at some people doing this kind of crafting fairly contemporaneously … [![](https://img.youtube.com/vi/uVyMnmu_sPs/hqdefault.jpg "Ethiopian cross design and making process") ](https://www.youtube.com/watch?v=uVyMnmu_sPs&t=639) [![](https://i.ytimg.com/vi/iLgHNOXnKlU/hqdefault.jpg "Making of an Ethiopian Coptic Cross - Lost Wax Process") ](https://www.youtube.com/watch?v=iLgHNOXnKlU) > [@Crafter\_Man](#): > > Very expensive, no doubt. No. When the Romans _wanted_ very expensive, you can tell. They weren’t subtle about it. ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [March 20, 2023, 5:12pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/105 "2023-03-20T17:12:18Z")
I want to look at the cites you provided but I’m having an eye problem right now and limiting my reading. I’m not sure lost wax was used. a solid core made of clay could support plates to mold the faces, plates made of clay but possibly other materials… The holes could have started from that form of casting. The nubs at the vertices may have been left open as the face plates were attached at their sides and provided simple vents for the poured metal. The core would have to be broken out, but possibly the face plates reused, don’t know if there would have been some other way to do it… Examining the samples for signs of post casting work could reveal information, the nubs were likely shaped after casting, and possibly the holes were ground out leading to their varying sizes. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [March 20, 2023, 5:22pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/106 "2023-03-20T17:22:47Z")
> [@TriPolar](#): > > I’m not sure lost wax was used All the archaeologists who’ve studied them are pretty sure it was, and based on my own experiences, I agree with them. They are obviously cast in one piece (at least the dodecahedron part). This is obvious when you look at the broken ones. I don’t even understand how your method is supposed to work. How do you remove the clay plates to leave voids to pour metal into? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [March 20, 2023, 5:43pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/107 "2023-03-20T17:43:52Z")
> [@MrDibble](#): > > I don’t even understand how your method is supposed to work. How do you remove the clay plates to leave voids to pour metal into?Y You don’t. The core and the plates form the mold leaving a void for the final shape. Wax could be used anyway, but may not be necessary. It’s a very complex shape already, heated sufficiently the wax can be melted out cleanly but it’s going to be a difficult pour. I’m quite sure the nubs provided vents for the cast metal however it was done. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [March 20, 2023, 6:23pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/108 "2023-03-20T18:23:12Z")
> [@TriPolar](#): > > The core and the plates form the mold leaving a void for the final shape So a complicated multi-part all-clay mould? Held together how? Sounds like a recipe for leaking molten bronze. But most importantly, _why_ do it this way, when lost wax casting existed and would have been perfectly adequate to the task? By which I mean, what is your _reason_ for discounting lost wax casting? > [@TriPolar](#): > > It’s a very complex shape already In terms of Roman bronzework, it really, really isn’t. > [@TriPolar](#): > > I’m quite sure the nubs provided vents for the cast metal however it was done. And what acted as vents for the ones where the nubs were post-casting add-ons attached with pins? ---
**Author:** ![TriPolar](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/tripolar/32/3008_2.png) [@TriPolar](https://boards.straightdope.com/u/TriPolar)\ **Post date:** [March 20, 2023, 6:50pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/109 "2023-03-20T18:50:17Z")
Sorry, typing and reading are difficult right now. I’ll try to outline what I’m saying to you more clearly. I don’t think lost wax is a necessity, but wax may have been used, it was likely to the predominant method of casting irregular shapes at the time. I think it’s clear that the core must be solid, probably just fired clay. If I were making one that core in the basic dodeca shape would have cylindrical protrusions extending out of every face, lets call those standoffs. If you did use wax that’s how the holes would have been formed. Let’s say you want 1/4" thick metal remaining on the faces, I’d have the posts extend at least 1/2", the first 1/4" the diameter of the hole, then a smaller diameter for the remaining length. Why? Because I’m sure the faces were formed from pre-made plates, probably just clay made in a simple mold that would include any detail to appear on the final faces of the dodeca. The plates would have holes in then that would fit right over the standoffs. Maybe they would apply wax on the core anyway to fill the space between the core and the plates to help hold it together while assembling, but they wouldn’t be carving detail into that wax. Then as the mold was assembled the faces would be joined with wet clay and then the mold baked again. After that I’d cover the whole thing with a lot more clay for reinforcement, but maybe they had a special molding material for that purpose. So why do it that way? Because it’s easier to create the decorative detail in clay plates ahead of time instead carving it into a 3D chunk of wax. Certainly even if they did use conventional lost wax technique they would have had standoffs on the core so the wax would have a uniform thickness so the core didn’t end up off center. On top there would be a large port on one vertex for pouring, all the other vertices would have small holes for vents and risers into which some amount of bronze would extend. The vertex at the very bottom would have to be pretty wide to make sure the metal was not impeded in flowing all the way to the bottom. The mold would certainly be preheated before the pour so if wax was used it would flow out at that point. Final work after cooling would include forming the nubs, removing any flash or other excess metal, and cleaning defects with abrasives. Hope you can understand what I’m describing. It’s not important whether was used or not, it’s a matter of practical construction of the molds. I don’t know how they’ve been examined but I’d certainly be on the lookout for shapes that had been welded together using molten bronze (brazing really) from pre-made bronze face plates. I’m surprised that wasn’t done. In general I’d like to know what kind of fluxing was done at the time. Using a high lead content bronze may indicate they needed a very high flow bronze to cast that shape. I wonder what the other metal content was along with many other details of the bronze casting process at the time. I know that casting large bronze parts was very complex, smaller items like these should not require large foundries and the highest possible heats but again, the issue with casting that shape is getting the metal flow through. They must have had a tall port on top for pouring, maybe with a funnel shape to hold more molten metal to help force the metal through the mold by gravity. ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [March 20, 2023, 7:19pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/110 "2023-03-20T19:19:50Z")
> [@TriPolar](#): > > So why do it that way? Because it’s easier to create the decorative detail in clay plates ahead of time instead carving it into a 3D chunk of wax. What? No, you’d carve the decorative detail into the sheet of wax _before_ you cut out the pentagons and join them. Why would you wait until after you’d joined them to do it? > [@TriPolar](#): > > Certainly even if they did use conventional lost wax technique they would have had standoffs on the core so the wax would have a uniform thickness so the core didn’t end up off center. What for? In conventional lost wax, you just build the entire final shape, then add sprues and vents as needed. There’s no need for these standoffs., the shape of the core is set when you add clay around the wax, there’s no way for it to get off centre. What you’re describing is some variant of the indirect lost wax technique, but that uses a high-detail core, and we can see the inside of these things, and they’re distinctly lacking in detail and crisp edges, that’s all on the outside. Did you see Mangetout’s page on his pewter copy? > [@TriPolar](#): > > I don’t know how they’ve been examined but I’d certainly be on the lookout for shapes that had been welded together using molten bronze (brazing really) from pre-made bronze face plates. It’s called flow fusion, and we know the Romans used the technique. But it was used on _large_ pieces of statuary, not small pieces - the heat required would probably melt smaller parts before the filler bronze could be added. So it’s not particularly surprising it wasn’t used here. The people who’ve examined these pieces say they’re made using direct lost wax casting. These are people who I think would recognize fused pieces if they saw them. ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [March 20, 2023, 8:06pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/111 "2023-03-20T20:06:31Z")
> [@Buck\_Godot](#): > > When I see stable rigid objects with holes in it, my intuition is that something is put in those holes and stands up. So I’m inclined to support that candle holder possibility. > > As to why it only appears in certain areas, perhaps it is a combination of utilitarian and cultural. Why buy an ordinary candle holder when you can buy one that also symbolizes the 12 virtues of Aristotle, or the 12 gods of olympus or whatever? Candles can be and were dangerous. You want them in in a container with wide stable base. These things are anything but. ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [March 20, 2023, 9:37pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/112 "2023-03-20T21:37:14Z")
Do you even use candles? I’d trust one to one of those puppies. Heck, i put candles in soft cake and in tall skinny candlesticks. Here’s the first image that popped up on a Google search > **[Easton Forged-Iron Taper Candleholders](https://www.potterybarn.com/m/products/easton-iron-taper-candlesticks/)** > > With its hand-forged look, Easton adds texture and a touch of old-world ambiance to any room. The substantial yet slender silhouette has a sculptural feel that’s equally stunning in an early American home, modern farmhouse, or minimalist Someone today is buying that. It looks a lot less stable than the dodecahedrond. The different sizes of the opposite holes argues against candlestick, but it doesn’t seem impossible. ---
**Author:** ![Al128](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/al128/32/16541_2.png) [@Al128](https://boards.straightdope.com/u/Al128)\ **Post date:** [March 20, 2023, 10:40pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/113 "2023-03-20T22:40:11Z")
> [@Lucas\_Jackson](#): > > Candles can be and were dangerous. You want them in in a container with wide stable base. These things are anything but. and normally you’d want a design that catches dripping/running hot wax before it stains a tablecloth (or something similar) - that is an aspect that I miss from the dode’s > [@puzzlegal](#): > > Someone today is buying that. It looks a lot less stable than the dodecahedrond. > > The different sizes of the opposite holes argues against candlestick, but it doesn’t seem impossible. I think today’s pedastrian use of candles is really distinct from the romans, who prob. used it for light at night … and might fall asleep with burning candles … today, you burn candles, stand next to them, sing a song or 2 and then blow them out … TLDR: same thing, but different usage pattern for candles ---
**Author:** ![Lucas\_Jackson](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/lucas_jackson/32/303_2.png) [@Lucas\_Jackson](https://boards.straightdope.com/u/Lucas_Jackson)\ **Post date:** [March 20, 2023, 11:21pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/114 "2023-03-20T23:21:47Z")
> [@puzzlegal](#): > > Someone today is buying that. It looks a lot less stable than the dodecahedrond. A weighted flared base is infinitely more stable. The weight of the candle alone would cause the dodecahedron to be a little tippy. It’s not that you couldn’t press one into service but had they been designed as such, a much better candleholder design would have been implemented. Heck, a cube would be far superior, could still have 6 aperture opening sizes and been much easier to construct. ---
**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:** [March 20, 2023, 11:49pm UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/115 "2023-03-20T23:49:16Z")
Well, whatever it was they were for, they probably weren’t too great at it, or they would have been used long enough for there to be a record of them, and spread across a wider area. Maybe they were the ancient equivalent of those “As seen on TV!” gizmos, that really don’t work well, but that some huckster is nonetheless able to sell until the public catches on. So maybe it was used to hold candles or whatever, because a lot of folks were unduly impressed by “Can hold XII different sizes of candle!”, but then the market dried up when one tipped over and burned down some poor schmuck’s house. ---
**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:** [March 21, 2023, 12:09am UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/116 "2023-03-21T00:09:34Z")
> [@MrDibble](#): > > . It’s basically Russel’s Amphora. I couldn’t find the definition of this phrase; please enlighten. Anyway, two puzzling things about the Roman dodecahedra stand out to me: First, if they were gauging holes why didn’t the Romans simply put different size holes in a flat piece of material like universally done today? Assembling twelve holes (or six pairs of opposed holes?) into a dodecahedron seems too much like a cute gimmick. Second, whatever the dodecahedra were used for, why did they _stop_ using them so completely that we don’t even remember what they were for? ---
**Author:** ![puzzlegal](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/puzzlegal/32/3827_2.png) [@puzzlegal](https://boards.straightdope.com/u/puzzlegal)\ **Post date:** [March 21, 2023, 12:20am UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/117 "2023-03-21T00:20:00Z")
> [@Al128](#): > > today, you burn candles, stand next to them, sing a song or 2 and then blow them out … Uh, i burn Sabbath candles until they go out. I burn yartzeit candles for a day. I burnt a memorial candle for a week when my mother died. I was fairly careful about placing the ones that burned overnight, and put them on a ceramic surface with nothing inflammable nearby. But they don’t leap out and attack things. Candles are pretty placid and mostly just stay where you put them. The flimsy birthday candles that are only held up by cake are less stable than a regular candle in one of those dodecahedrons would be. ---
**Author:** ![dtilque](https://avatars.discourse-cdn.com/v4/letter/d/d6d6ee/32.png) [@dtilque](https://boards.straightdope.com/u/dtilque)\ **Post date:** [March 21, 2023, 12:24am UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/118 "2023-03-21T00:24:36Z")
> [@Lumpy](#): > > > [@MrDibble](#): > > > > It’s basically Russel’s Amphora. > > I couldn’t find the definition of this phrase; please enlighten. A reference to > **[Russell's teapot](https://en.wikipedia.org/wiki/Russell%27s_teapot)** > > Russell's teapot is an analogy, formulated by the philosopher Bertrand Russell (1872–1970), to illustrate that the philosophic burden of proof lies upon a person making empirically unfalsifiable claims, rather than shifting the burden of disproof to others. > Russell specifically applied his analogy in the context of religion. He wrote that if he were to assert, without offering proof, that a teapot, too small to be seen by telescopes, orbits the Sun somewhere in space between the Earth and Ma... ---
**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:** [March 21, 2023, 12:41am UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/119 "2023-03-21T00:41:05Z")
> [@dtilque](#): > > > [@Lumpy](#): > > > > > [@MrDibble](#): > > > > > > It’s basically Russel’s Amphora. > > > > I couldn’t find the definition of this phrase; please enlighten. > > A reference to > > [Russell's teapot - Wikipedia](https://en.wikipedia.org/wiki/Russell%27s_teapot) I found exactly one other hit for “Russell’s Amphora”: a 2012 post on a site called The Orbit in a thread mocking the movie “Hercules” by a Twitter user named @pzmyers. That wasn’t you was it? ---
**Author:** ![MrDibble](https://sea3.discourse-cdn.com/straightdope/user_avatar/boards.straightdope.com/mrdibble/32/114_2.png) [@MrDibble](https://boards.straightdope.com/u/MrDibble)\ **Post date:** [March 21, 2023, 6:52am UTC](https://boards.straightdope.com/t/roman-dodecahedrons/980459/120 "2023-03-21T06:52:18Z")
Yes, it’s a reference to Russell’s Teapot. No, that wasn’t me, it was probably [this guy](https://freethoughtblogs.com/pharyngula/). > [@Lumpy](#): > > Second, whatever the dodecahedra were used for, why did they _stop_ using them so completely that we don’t even remember what they were for? One theory that addresses this is that they were cultic. Look at when they’re found: the _late_ Imperial period, and in some the last parts of theWestern Empire to fully Christianize. If they were secret tokens of relict polytheist pagan cultists, that might explain why they a) weren’t written about b) only occur in particular regions c) die out with the final ascendancy of the Church d) are treated as precious personal items That’s just a theory I’ve read, mind you, I’m agnostic myself, but it does address something other theories don’t, and I don’t share Mangetout’s cynicism about archaeology’s use of religion as a default. Doesn’t really address the form, though. [Previous page](https://boards.straightdope.com/t/roman-dodecahedrons/980459.md?page=5) [Next page](https://boards.straightdope.com/t/roman-dodecahedrons/980459.md?page=7)