
Mathematical View of the New Pound Coin - CarolineW
http://seanelvidge.com/2016/11/new-pound-coin/
======
gjm11
Since the page is inaccessible right now, here's the tl;dr (though it's not
long at all):

The UK's new £1 coin has 12 sides. That makes it impossible for it to be (like
the 7-sided 50p and 20p coins) a shape of constant diameter, which might make
it roll less well and make things harder for the makers of vending machines.

When OP heard that the new coin was going to be 12-sided, he wrote to the
Royal Mint. When the final design came out, it turned out that they'd taken
this objection into account but found that a 12-sided coin with curved sides
and rounded corners rolls well enough. Very good, but OP would have been
happier with an odd number of sides. The end.

(Is the constant-diameter property actually relevant to vending machines? It
seems to me that unless you're trying to fit the coin down a "tunnel" of
absolutely minimal size, what matters is how close it is to constant _radius_
\-- i.e., how nearly circular -- and constant diameter is a red herring.)

~~~
Doxin
> Is the constant-diameter property actually relevant to vending machines? It
> seems to me that unless you're trying to fit the coin down a "tunnel" of
> absolutely minimal size

A lot of cheap coin-op mechanisms put coins through an exactly sized tunnel as
first step, so while it's probably not critical, it would be nice to have the
coins be constant diameter as now you either need to configure your coin
acceptor to be more slack or install a new one altogether.

------
helthanatos
But why not make the whole coin round?

~~~
Latty
Different shapes make for easier identification without looking at the coin
(good for the blind, people trying to find a coin in a wallet, etc...), and
are harder to fake.

It is also, apparently, a reference to the shape of the old threepenny bit.

~~~
Meic
Which is what a pound will be worth post-Brexit.

