Stone Age frustrum

An archaeological dig near Moscow has yielded some impressive Stone Age artifacts.

The site at Zaraysk, 150km south-east of Moscow, has yielded figurines and carvings on mammoth tusks..

The figurines are a type of "Venus" statuette, examples of which have been found in locations ranging from the mountains of Spain as far east as Siberia. However, their cultural significance remains a point of debate among anthropologists...

Also among the finds was an object carved from mammoth ivory, shaped like a cone with its top removed. The cone is densely ornamented and has a hole running through its centre.

The authors note that the object is unique among Palaeolithic artefacts. "The function of this decorated object remains a puzzle," they say.

It's a frustrum. A Stone Age frustrum. Clearly they were using it to teach Euclidean geometry.