re "its rings". I'm never quite sure whether to correct grammar/spelling or not in HN comments. On the one hand I know there are lots of people here for whom English is a second language and who might find it useful. On the other hand, I don't want to appear dickish. At work I generally ask my non-native-English-speaking colleagues if they want me to point out errors and then act accordingly. And every now and then one of them challenges my correction and I discover I'm wrong ;-)