> The question is, how closely do the sizes of the two objects match? My initial guess was they were used as a retrievable projectile for hunting and eventuall

> The question is, how closely do the sizes of the two objects match? My initial guess was they were used as a retrievable projectile for hunting and eventually evolved into symbolic items, because they are just the right size for throwing; any larger would make them unwieldy, any smaller less effective. But a lot of them are exactly the same size. So there must be a reason for this precision. "Many of the late Neolithic stone balls have diameters differing by only a millimetre. The discovery of this led to the suggestion that they might have been meant to be used together. By plotting the find sites on a map it can be demonstrated that often these petrospheres were located in the vicinity of Neolithic recumbent stone circles. Models using small wooden balls placed in a groove in parallel longitudinal pieces of wood 'sleepers' with a carrying board above have shown such megalith transport to be practical in some situations."[1] Following that wiki section's footnote reveals this is Andrew Young's theory [2], which does, at least, explain the need for such close precision, at least for the ones that have nearly identical diameters. [1] https://en.wikipedia.org/wiki/Carved_stone_balls#Megalith_construction_aid https://en.wikipedia.org/wiki/Carved_stone_balls#Megalith_co... [2] https://www.sciencedaily.com/releases/2010/11/101130010931.htm https://www.sciencedaily.com/releases/2010/11/101130010931.h...