Brass dodecahedrons keep turning up in the European soil. They're of Roman antiquity, but no-one knows for sure what they were for. Thankfully, "mundane ornamentation or maybe a childrens' toy" is not what anyone wants to hear. Mental Floss:
Historians have found no written documentation of the dodecahedrons in any historical sources. That void has encouraged dozens of competing, and sometimes colorful, theories about their purpose, from military banner ornaments to candleholders to props used in magic spells. … Amelia Sparavigna, a physicist at Italy's Politecnico di Torino, thinks the dodecahedrons were used by the Roman military as a type of rangefinder. In research published on the online repository arXiv in 2012, Sparavigna argued that they could have been used to calculate the distance to an object of known size (such as a military banner or an artillery weapon) by looking through pairs of the dodecahedrons' differently sized holes, until the object and the edges of the two circles in the dodecahedron aligned. Theoretically, only one set of holes for a given distance would line up, according to Sparavigna.
Or, perhaps, an astronomic measuring instrument for determining the optimal sowing date for winter grain. [romandodecahedron.com]
My favorite explanation: a glove-knitting gadget.
Photo: Lokilech (CC BY-SA 3.0)