What was the earliest polygonal coin in your country or area of expertise?

[Ice Torch]

I'm also interested in how many polygonal varieties there are. I've
started an topic on it - with images - and got our forum members
joining in. So far we've got up to 16 sides, then there's a gap until
we come to 22 sides and 24 sides. Click on the link to have a look:

http://www.worldofcoins.eu/forum/index.php/topic,9889.0.html

Do you know of any others? (And before you tell me there are two sides
to every coin, I've dealt with that one in the topic!).

History, production, numismatic fashion, the trend towards pretend-
polygonal coins (circular coins with a polygonal inner rim), vending
machine use - I've tried to deal with these, but I still have gaps and
questions. Have I missed anything?

Phil.