In geometry, a dodecahedron (Greek δωδεκάεδρον, from δώδεκα dōdeka "twelve" + ἕδρα hédra "base", "seat" or "face") is any polyhedron with twelve flat faces. The most familiar dodecahedron is the regular dodecahedron, which is a Platonic solid. There are also three regular star dodecahedra, which are constructed as stellations of the convex form. All of these have icosahedral symmetry, order 120.

The pyritohedron is an irregular pentagonal dodecahedron, having the same topology as the regular one but pyritohedral symmetry while the tetartoid has tetrahedral symmetry. The rhombic dodecahedron, seen as a limiting case of the pyritohedron has octahedral symmetry. The elongated dodecahedron and trapezo-rhombic dodecahedron variations, along with the rhombic dodecahedra are space-filling. There are a large number of other dodecahedra.

https://en.wikipedia.org/wiki/Dodecahedron

A regular dodecahedron or pentagonal dodecahedron is a dodecahedron that is regular composed of twelve regular pentagonal faces, with three meeting at each vertex, and is represented by the Schläfli symbol {5,3}. It is one of the five Platonic solids. It has 12 faces, 20 vertices, 30 edges, and 160 diagonals (60 face diagonals, 100 space diagonals).^[1]

All across Northern Europe, curious dodecahedral objects have been found at Roman archaeological sites. The original purpose of these intricate objects is not known.

In this project, I will attempt to make a replica dodecahedron - to see if I can work out what they can and cannot be used for.

Roman Dodecahedra

Dozens of these objects have been found at archaeological sites throughout Northern Europe - usually only one per site - and sometimes broken or incomplete, but it's a delicious mystery that we have these beautiful and intricate devices spread across a wide region, and yet, nobody knows for sure what they do.

Here's a picture of a typical Roman Dodecahedron from Germany:

Theories

Theories abound, of course - including 'artifact of religious purpose' (which seems to me to be synonymous with "we haven't a clue" in the vocabulary of archaeologists) - but also: pipe measuring device, surveying tool, tent pole joint, headpiece for a standard or staff, gaming device, weapon, etc.

And of course, I have a few theories of my own - some of which have (in my mind) increased in credibility over the course of my attempt to make a replica - others have become less likely

What It Probably Isn't

Many people, on first seeing a picture of these objects, leap to the conclusion that it's intended for throwing or rolling - like a gaming die (indeed, twelve-sided dice are not uncommon nowadays) - however, I don't believe it can be that - as it's big (the size of an orange), heavy (usually made from bronze) and a little fragile - cast metal is typically brittle - if this thing was for throwing, the corner balls could be expected to break off on first or second use, which hardly seems probable, given the effort required in making it.

Taper Gauge is another popular notion, however (and this only really hit home for me when I started making one) the pairs of opposing holes are nearly the same size - in fact, they're similar enough in size that it perhaps could be argued that they were intended to be the same, but turned out a little different just because of engineering tolerances etc.

Retort - for a little while, I really thought I'd got it - I'd seen small Roman ointment or medicine bottles in museums that were cone shaped or elongated ovoid, with pointed bases - and I imagined them resting in one of these dodecahedra - perhaps after it had first been heated to make an oile or wax-based ointment more liquid - the physician placing the awkward pointed bottle back in the retort whilst working on his patient.

However, the nearly-matching opposed hole sizes seem to make this less likely - unless the Romans also had test tubes...

Universal Eggcup - We all know the Romans were fond of a wide variety of foods, so I was momentarily tempted to imagine this being a device for securely holding boiled eggs of any size from Quail to Swan. But I don't know if the Romans even ate boiled eggs in that way - besides, it doesn't explain why there's seemingly only ever one of these found in any particular place.

Apprentice's Materpiece

It may be that these objects exist for the sole purpose of being difficult to make - there are many different challenges to overcome when making one (keeping the wax workable, getting everything the right size, accidental breakage of the delicate wax form whilst constructing it (in fact, I discovered myself that as more of the corner balls are added, it gets progressively harder to work on the form without damaging it).

Furthermore, different variants of dodecahedra exist, with quite a wide variety of different forms and measurements - it's really hard to imagine a single practical purpose for which they would all be suited, other than as a showpiece.

Imagine a metalworker needing to prove his capability in casting, finishing, soldering, etc - what better than a small, hand-portable demonstration piece?

Additionally, the decoration of these items varies - some are plain - others have rings embossed concentrically around the holes, others have small rings arranged in the corner spaces around the holes - it's again not hard to imagine that a written specification saying something like 'each hole is to be surrounded by rings' being interpreted as meaning concentric rings, or a collection of small rings encircling each hole.

Of course, it's all speculation, as nothing seems to have been written about these dodecahedra, but maybe that's not true - maybe it's hiding in plain sight - it could be that stumbling upon the purpose of these objects could be the key to unlocking the meaning of some previously-obscure writing somewhere - not like a secret code as in the movies - just something that doesn't jump out as meaningful, until you know exactly what it's talking about.

http://atomicshrimp.com/post/2013/03/03/Making-A-Replica-Roman-Dodecahedron