Here's what i learned about it from Wikipedia:
A Roman dodecahedron or Gallo-Roman Dodecahedron is a small hollow object made of copper alloy which has been cast into a dodecahedral shape: twelve flat pentagonal faces, each face having a circular hole of varying diameter in the middle, the holes connecting to the hollow center. Roman dodecahedra date from the 2nd to 4th centuries AD.
Since the first dodecahedron was found in 1739, at least 116 similar objects have been found from Wales to Hungary and Spain and to the east of Italy, with most found in Germany and France. Ranging from 4 to 11 centimetres (1.6 to 4.3 in) in size.
No mention of them has been found in contemporary accounts or pictures of the time. Speculated uses include as a candlestick holder (wax was found inside two examples); dice; survey instruments for estimating distances to (or sizes of) distant objects; devices for determining the optimal sowing date for winter grain; gauges to calibrate water pipes or army standard bases. Use as a measuring instrument of any kind seems improbable since the dodecahedra were not standardised and come in many sizes and arrangements of their openings. It has also been suggested that they may have been religious artifacts, or even fortune-telling devices. This latter speculation is based on the fact that most of the examples have been found in Gallo-Roman sites. Several dodecahedra were found in coin hoards, providing evidence that their owners considered them valuable objects. These artifacts have mainly been found in cold-climate areas of Roman habitation; leading some to speculate they may have been used as a knitting framework (cf. knitting Nancy). It has been suggested that the varying size of the openings might possibly correlate with the variety in finger sizes.
What I'd like to do is buy a replica to use on my desk. It's small enough to easily fit and looks very odd, a sure conversation piece. I'll have to find a good quality reasonably priced one. I've seen 3D printed plastic replicas that look good but seem overpriced.
Today I'm giving myself my weekly SCIG injection. I'm having trouble with two of the four injection sites. They have blood in the tubes which means they are in small veins instead of being subcutaneous. I pulled out the needles and reinserted them. One turned clear so it must be okay. The other still has a small bit of blood. Maybe I should disconnect it, but I'll leave it in for now. The entire procedure takes about four hours. I'm going to have some lunch now.