Now we come to matters of practicality. How easy or difficult is it to produce a polygonal numismatic item? Is it more costly than producing standard circular ones?
Nowadays we have to consider vending machines, of course. A coin will only be accepted by a vending machine if it has constant diameter, or, in plain English, if it rolls. I do remember our member Tony Clayton trying to explain aspects of this in another topic. He struggled to explain it in a way that the other members could understand. Whether that was because the subtleties of such subjects are difficult to express in language, or because the concept he was trying to express was quite simply beyond me, or both, I simply don’t know. In any case, this means that some polygons, such as triangles, squares and rectangles, cannot be used in vending machines. But does that mean that every other polygonal coin, from pentagons upwards, could in theory be used in a vending machine if properly minted?
Are there any more technical subtleties? I notice that a heptagon can be used in vending machines, because we have heptagonal 50 pence and 20 pence coins in the UK. However, the official name for them is “equilateral curve heptagons”. If their edges were not curved, would vending machines still be able to accept them? I don’t know the answer to that one.