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Comment by decadentcactus | Hacker News Reader

The different sizes, I'm not entirely sure but I thought they were for blind people... somehow. Or I might be making that up.

This from Wikipedia also explains my dislike for $1:

    Approximately 42% of all U.S. currency produced in 2009 were one-dollar bills.

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That is correct. Differently sized bills enable blind users to differentiate them without having to rely upon the honesty of a cashier or a complicated filing scheme (and, additionally, allow sighted people to more-easily differentiate denominations in low-light conditions).

Edit: specifically, I learned about this from Gordon Legge[1], the chair of the psychology department at the University of Minnesota when I took a graduate level course on human-machine interaction from him back in 2002 or 2003. I lucked out and had a very forward-thinking advisor in the Computer Science department who let me apply Professor Legge's class to my Senior year electives ;)

[1] see http://en.wikipedia.org/wiki/Gordon_Legge and http://vision.psych.umn.edu/users/legge/ for more on him.

Different-sized notes also defeat counterfeiters who bleach smaller denominations and print a higher one.

The different sizes make it possible to select a given denomination without either doing an O(n) lookup, or having to keep your wallet sorted.

What sort of barbarian programmer doesn't sort his bills? Unthinkable.

Having different sized bills is kind of like keeping your money in a visual/tactile hash-table. An array is the wrong data structure for your wallet!

The kind that profiles. The common case to optimize for may be insertion (especially with US $1 notes) rather than withdrawl. Semi-sorting by putting all change at the front while withdrawing for payment from the large bills at the rear is a decent tradeoff.

That's what I've found myself having to do. I've never had to have a sorting strategy before living in the US. The lack of distinction between notes is frustrating. I love it when Americans tell me they have colored notes too.

I still can't understand the preference for one dollar notes. Whenever I use a washing or vending machine I need to flatten out and align a dollar bill or insert dozens of quarters. Every few weeks I have to buy a couple of rolls of quarters from the bank. I paid a cashier with dollar coins yesterday and she did a double take and inspected each coin.

You actually got me to realize how natural it is for me to sort my bank notes. I also put older notes on the top of the stack so that they get out of it first.

I can't be bothered to manually sort something. Tell me when I can just call wallet.sort().

My grandfather was blind and had to resort to his family telling him what the denominations were beforehand and then he folded the bills into different sizes. Apparently one day a cashier attempted to scam him by claiming the bill he gave was too small. Different sized bills would be helpful in that situation.

The old Canadian bills already had a braille-like pattern of raised dots that allow blind people to identify denominations without assistance.

http://en.wikipedia.org/wiki/Canadian_currency_tactile_featu...

Hopefully the new bills will retain this feature.

As for the good ol' American green-back. Americans are excessively conservative when it comes to their currency. Just look at how long it took them to add colors other than green! At least we no longer have to put up with Americans mocking our currencies for being multi-colored monopoly bills. If americans are skeptical of polymer bills I can only take that as a good sign for these new Canadian bills.

I usually have a bunch of $1 bills in my wallet. I'm not sure I'd want $1 coins, given that they're heavier than a paper bill and are more likely to get lost.

Not at all. It's great, actually. My toonies, loonies, quarters, etc go in my change jar. My wallet is for bills (>= $5). I never carry change with me, and so don't have to worry about the hassle, and when I run out of money I have easily $50 in my change jar, which is enough for a frugal grocery trip. The proliferation of self-checkout stands also makes paying for $50 worth of groceries in coins slightly less embarrassing.

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