For those allergic to these things, let me just say that this post is not going to become a Mac versus Windows item. Having said that, I have been a Macintosh user for a very long time. One of the things that has always attracted me to the Macintosh was the superior usability of the Mac platform. The foundations for this were laid in what are now the prehistoric times of computing. While Windows has caught up to some degree, it's still a skin-deep appropriation of the user interface design principles that made the classic Macintosh interface what it was. The difference between the Mac and Windows has become even smaller with Mac OS X, which in many cases is a step backwards in terms of usability. I can understand that Microsoft has had trouble acquiring a deep understanding of user interface design, but Apple should have known better. Designing good user interfaces is hard work, but there has been a lot of research done in the quarter century since mice and GUIs were invented at Xerox PARC.

User interface design is a surprisingly neglected field, even in places where one would expect a large premium to have been placed on getting things right. The canonical example of VCRs being hard to program is harmless. But even in aviation user interface design can go horribly wrong. The crash of a commuter plane in Switzerland about a year ago was due to a poorly designed display. One display panel for landing approaches had two modes: one to show the rate of descent, the other the angle of descent. So a display of 3.2 could mean either a descent of 320 ft/min or 3.2 degrees, depending on which mode the display was in, without any clear identification of which mode was being used. The pilots had not had many flying hours in the type of aircraft, and thought they had the display in the other mode than was showing.

The best user interaces are those that you don't even notice. A hammer has a simple user interface. But even something as seemingly simple as light switches can be infuriating. Many a time have I had to wrestle with light switches in hotel rooms before I got them to work. Money has a user interface too, although in this case it's just the design of the notes and coins that matters. As regular readers of this blog will know, I am not a big fan of European Monetary Union as it exists now, but I am also unhappy with the usability of the coins specifically.

Having used euro coins for almost a year now, I still spend way too much time trying to find the right coins. This is an inordinately long time to get used to the coins, because whenever I have to use other currencies, I seem to become acquainted with the coins within days. Is it just a spill-over from my dislike for the concept of the euro?

It's more of a design problem with the euro coins. The design of euro coins was an excellent opportunity to come up with new coins and designers had a field day. The winning design is a nice, logical ordered sequence. There are three sets of coins: the 1, 2 and 5 cent pieces are reddish in color, the 10, 20 and 50 cent pieces are golden/yellow and the 1 and 2 euro coins are two-colored. The coins all have distinguishing marks with differing edges and different thicknesses. So clearly the designers did have distinguishability in mind.

But why does it not work? There are two big problems. The first is that there are too many coins. There are 8 in total, compared to the 6 we used to have in the times of the guilder. US coins are especially parsimonious with only 4 coins in common use. Sacagawea dollars are too rare to be counted. But simply the number of different coins can't be the whole story, because German marks came in the same 1, 2, 5 series up to 5 marks. So there were even more of them than euros. The British pound coins have the same face values as the euro coins, yet it's still easier to find the right coin when I am in Britain than when I am in the eurozone.

This leads to the second big problem: the euro coins are too logically arranged. They're too ordered. For all the efforts to make them different, they're still too similar in shape, size, color and weight. The old Dutch dime and the US dime shared the trait of being very small. There's no logical reason to make the dime smaller than a penny, or why a 50 pence piece should be octogonal. The haphazard historical evolution of coins led to an almost random assortment of coins in shape, size and weight. This large disparity made recognizing coins easier, especially when fumbling around under poor lighting conditions in your wallet. I find it hard to tell the difference between a 10 and 20 euro cent piece, or between 20 and 50 cents in practice. Even the different colors of the 1, 2, 5 series and the 10, 20, 50 series become less apparent in poor light. The sizes are not sufficiently different to tell them apart quickly. Even the difference between a 1 and 2 euro coin can be tricky to tell from just seeing them half-obscured at an acute angle. Yet that's how they end up jumbled in my wallet.

Euro coins need to be redesigned to alleviate this problem. We need some whacky coins, like the old Dutch rijksdaalder (2.5 guilders) which was much larger than the 1 guilder piece. Or make a big coin like the 5 mark, 50 pence and a small one like the dime. One thing though: don't make them too heavy. I hate to carry around one pound coins, as they weigh so much. And get rid of the 1 cent piece. I always end up with large quantities of those (much like pennies in the US), and they're just a damn nuisance.

It's not going to happen of course. The design of the notes and coins was politically sensitive, so re-opening this issue is not going to happen for a very long time. I also suspect the political sensitivity of the initial design led to the situation we have now. The euro coins would never been allowed to look like any existing coins of the legacy currencies, so the safe escape route of making them logical and orderly was an obvious way out. Except I don't think it works in practice. Then again, this would not be the first time that political expediency triumphs over practical concerns. I would expect that there has been research into the usability of coins and that coins designers are aware of it. But as the aircraft example shows, neither the research nor the awareness of it can be taken for granted.