HN guidelines for submissions are to post the original source for a story, which is linked in the article. <a href="http://www.cs.tau.ac.il/~tromer/acoustic/" rel="nofollow">http://www.cs.tau.ac.il/~tromer/acoustic/</a> This has been posted efore with lots of discussion. <a href="http://news.ycombinator.com/item?id=6927905" rel="nofollow">http://news.ycombinator.com/item?id=6927905</a>