Forepart of a winged boar right
Quadripartite incuse square
When I first read that in Seaford's "Money and the Early Greek Mind" I have to admit I had the wrong end of the stick! I now know the "spits" referred to were made of iron and were of the type used for roasting meat.
You see a "spit", or "obelos", gave its name to the small Greek silver coin we know as the obol. Given that small change could be carried in the mouth then my misunderstanding was, I think, excusable.
The term "drachma" means handful, particularly six (as noted by Aristotle, for example), and so we get "obeliskon drachmai" - a handful of spits - being used in temple inventories and inscriptions. These must be referring to bundles of iron rods, not the grudging payment in the hand of small silver coins. It was only later that these two terms began to have a specific reference to money.