If this wasn't a science page, if this happened 3,000 years ago in, say, a Middle Eastern desert, I would call it a Miracle. But it's not. It's just a plain, ordinary moment of "wow!"

First, the beginner's version. A man takes a bunch of metronomes, sets them ticking in different ways, then — and this is the crucial part — he lifts them collectively off the table, so their different motions now start to offset each other. And this happens ...Read More »