The Sugar desktop environment works on the metaphor of circles. It took me a few minutes to figure them out, but as soon as I was pointed at the right button (a dot, of all things), I was off and running.
The irony? Several years ago I had a paper published in the ACM‘s Ubiquity entitled, “Why Do Current Graphical User Interfaces Not Work Naturally & How They Can Be Fixed?“.
It’s nice to see some thoughts I once had published on ergonomics turn out to be practical in the Real World™ 🙂