I have three bank accounts (personal, business, shared), which means three ATM cards. In addition I have a 'chippas' card to pay at, for example, parking ticket and coffee machines. All in all I have four cards from the same bank in my wallet. My bank (the Dutch Postbank, currently being rebranded into ING) had the wonderful tradition of slightly updating the graphic design of its cards every three or four years or so. To me this was wonderful, because that usually meant that each of my cards had a different design, and I could distinguish them easily. Until recently one of my cards got stolen and another one broke. All of a sudden I found myself with a wallet full of very similarly looking cards, resulting in hastily searching my wallet for the right card, or even using the wrong cards at ATMs when I was not yet completely awake yet (morning commute). The problem is worsened by the fact that when the cards are in your wallet, you can't see the account numbers, only the edges (see picture above).

A redesign
Of course I could order a customized card for each account, but that seems somewhat over the top and a bit expensive (about 10 Euro per card). That got me thinking. The bank could add a small 'indicator' on the corner of each card that makes them easily distinguishable, even when they're in your wallet. It doesn't need to be fancy, or extensive. With my limited graphics design skills I came up with the (Photoshopped) solution as shown below. I tried to use colors that would not completely freak out the brand cops (as you can see in the photo at the bottom, the markers do not stand out that much), but still are relatively easy to distinguish. Of course, using red, green and yellow would have made it even easier, but if a redesign should stand any chance of being implemented, you have to take aesthetics into account as well. As it seems unlikely that any bank will adopt this solution with regard to the lack of direct financial benefit to them, I would like to point out that some colored adhesive tape or a permanent marker does the trick as well.