Vending some trouble
Following on the latest meme, I’m going to link to a page talking about vending machines. Microsoft employee Raymond Chen discusses the pitfalls of user interface design for vending machines:
The columns are labelled 1 through 10. That means that if you want to buy product C10, you have to push the buttons “C” and “10”. But in our modern keyboard-based world, there is no “10” key. Instead, people type “1” followed by “0”.
What happens if you type “C”+“1”+“0”? After you type the “1”, product C1 drops. Then you realize that there is no “0” key. And you bought the wrong product.
Read the rest of Raymond’s article, then read his followup and sequel on house door locks.