For what purpose? :)

Carved stone ball, Towie, Aberdeenshire by National Museums Scotland on Sketchfab

Some of the most enigmatic human-made objects from Europe's late Stone Age — intricately carved balls of stone, each about the size of a baseball — continue to baffle archaeologists more than 200 years after they were first discovered.

Such proposals have included the possibility that they were made as the stone heads for crushing weapons, or standardized weights for Neolithic traders, or rollers for the transport of the giant stones used in megalithic monuments.

One theory is that the knobs on many of the carved stone balls were wound with twine or sinew, which allowed them to be thrown like slings or South American bolas. Other theories describe the balls as objects of religious devotion or symbols of social status.

Here's a set of them.

Neolithic carved stone balls, Scotland by National Museums Scotland on Sketchfab

Just another mystery for us rubes to ponder in the year of our lord 2018. :)