Not to be outdone by a bunch of mere snakes, the folks at Boston Dynamics have built a four-legged walking robot called the BigDog. When it’s simply making its way over uneven terrain, it’s impressive. When it’s scrambling to recover its balance — after a receiving hard shove to its midsection, or slipping on an icy patch — it’s positively spooky. The damn thing moves like a living animal. I find my heart going out to it as it would to any creature in distress, despite the fact that I know full well it’s just a machine.