Half a croissant, on a plate, with a sign in front of it saying '50c'
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Concentric coins

Do away with messy rolls.
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I was thinking about the problem of the 70p coin. The problem is two coins need to be hybridized. Money with holes is nothing new. What is needed is holes in the coins big enough to fit other coins into. I propose that coins be made with holes allowing concentric concatenization of coins. The 25c quarter would have a hole big enough to allow a dime, making a 35c coin, good for a phone call. The 50c would have a hole for a 25c coin, thus allowing 75c coin or 85c if the dime is included. Variations of this could be done for other coinage, allowing the 70p bus coin to be made from 2 coins of lesser value.

Other benefits - the nice open coins would make fabulous necklaces.

Drawbacks - only very round things could be depicted on coins. Except for the smallest, most central coins. Probably several versions would be necessary for the smallest coin, to allow the various presidents equal time. This would not be a problem in Britain, where it is always the queen on there.

bungston, Jul 22 2003

Connecting Coins http://www.halfbake.../Connecting_20Coins
[phoenix, Oct 05 2004]

70p bus fare and 30p coin http://www.halfbake...om/idea/30p_20piece
[bungston, Oct 05 2004]

Canadian $2 coin http://www.mint.ca/...htm?cookie%5Ftest=1
Concentric rings. "The outer ring of the two dollar coin is nickel and the inner core is aluminum bronze" [waugsqueke]

Electromagnetic "footprint" http://www.copper.o...Ct89/newcoin89.html
Straying a little off topic - regarding design of the new dollar coin and electromagnetic signature. Not positive how this is used by coinop machines. [waugsqueke, Oct 05 2004, last modified Oct 06 2004]

Electromagnetic "footprint" http://www.copper.o...Ct89/newcoin89.html
Straying a little off topic - regarding design of the new dollar coin and electromagnetic signature. Not positive how this is used by coinop machines. [bungston, Oct 05 2004]

[link]






       // only very round things could be depicted on coins. //   

       That's even cooler! Then you'd need a [matching!] set of coins to complete the picture. Maybe a set of 1996 coins would form a picture of an eagle, and a set of 1997 coins would form a picture of a bull, etc.
phundug, Jul 22 2003
  

       If we're doing away with messy rolls, then surely the answer is croissants? They'd stack better, too.   

       Also, you seem undecided whether you're talking about cents or pence...
DrCurry, Jul 22 2003
  

       Fingers. Right....
DeathNinja, Jul 22 2003
  

       Inspiration!
phoenix, Jul 22 2003
  

       I do like the fact that radius could track value without the typical squarefold mass proportionality. But variation in ambient temperature might make it hard to nest coins precisely (could one use a series of metals like those in the old two-tone ringed Italian and French coins, which have complementary density changes with temperature?). And maybe wide-pitch screwmounts would allow more secure coupling.
n-pearson, Jul 22 2003
  

       Screwmounts - yes! That is exactly what is needed.
bungston, Jul 22 2003
  

       I thought that US coin sorters also work on electrical impedence. I seem to remember that is was tricky getting a gold color alloy for the new Saccy dollar to match the impedence of the old susan anthony dollars they replaced. The reason this was important was for coin machine operators.
bungston, Jul 22 2003
  

       re: [waugs] Canadian $2 coin link--the centre does not pop out as in [bung's] idea, however, if you peel it open there is chocolate inside.
lintkeeper2, Jul 22 2003
  

       Apologies for any confusion - I did not mean to suggest that the CDN $2 center pops out. I posted it as an example of what a two-tier concentric coin looks like.
waugsqueke, Jul 22 2003
  

       //I thought that US coin sorters also work on electrical impedence.//   

       It's certainly possible for them to do so, but I think most are just mechanical. Probably depends a lot on the application.   

       BTW, I wonder whether impedance-based coin sorters have special program to deal with "real" quarters?
supercat, Jul 23 2003
  

       You run into a lot of fake quarters, [supercat]?
bungston, Jul 23 2003
  

       Used to be a big problem. Now it's mostly fake $50 bills.
DrCurry, Jul 23 2003
  

       [fogfreak], I'd worry that magnetized coin stacks might screw with data on personal cards in folks' pockets.
n-pearson, Jul 23 2003
  

       The centre of a Canadian two dollar coin does pop out.

If you hit it hard enough.
  

       Hey, now.
lintkeeper2, Jul 23 2003
  
      
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