Minter needed, must own straightedge, compass, and additional tool.

December 9, 2015 9:01 AM

An Alphabet of Heptagons By heptagons, I mean seven-sided coins. OK, it won't be a full alphabet - it will have a few gaps, and I may have to cheat in some cases. When I've finished the alphabet, I'll open up the topic to comments.
posted by Wolfdog (10 comments total)

As a big fan and a major backer of sevenfold radial symmetry, and as someone who enjoys griping on the Internet, I want to say that the Gibraltar coin is upsetting to me, in the same way that nice seven-way alloy wheels are ruined by the five-bolt arrangement.
posted by Rat Spatula at 9:13 AM on December 9, 2015

Five dolphins, eight flowers. It's almost like they were intentionally trolling.
posted by explosion at 9:42 AM on December 9, 2015 [2 favorites]

Haiti seems to be playing that same game.
posted by sparklemotion at 9:49 AM on December 9, 2015

Although it's not mentioned in the linked page, as far as I can see, coins with an odd number of sides have the advantage that they can be designed to have a constant or very-nearly constant diameter. Even-sided polygons have wider parts (from vertex to opposite vertex) and narrower parts (from center of a side to center of opposite side) which presents a difficulty for vending machines and other coin-accepting channels.
posted by Wolfdog at 10:09 AM on December 9, 2015 [4 favorites]

Yes, Wolfdog, the 7 sided UK and Commonwealth coins have the arc radius of the curved side the same as the width so that they have a (near) constant diameter. They roll beautifully.
posted by scruss at 10:30 AM on December 9, 2015

Yes, they are Reuleaux polygons (previously).
posted by wilko at 11:07 AM on December 9, 2015

Wolfdog: "Although it's not mentioned in the linked page, as far as I can see, coins with an odd number of sides have the advantage that they can be designed to have a constant or very-nearly constant diameter."

I was wondering why they seemed to be so popular.
posted by Rock Steady at 12:55 PM on December 9, 2015

> they are Reuleaux polygons

ORLX?
posted by scruss at 1:43 PM on December 9, 2015 [2 favorites]

Westerosi coins should all look like these.
posted by ChurchHatesTucker at 5:57 PM on December 9, 2015

Oh god. Oh no.

I feel another collection coming on.
posted by rifflesby at 10:16 PM on December 9, 2015