How China Controlled the Coronavirus

Afew days before my return to classroom teaching at Sichuan University, I was biking across a deserted stretch of campus when I encountered a robot. The blocky machine stood about chest-high, on four wheels, not quite as long as a golf cart. In front was a T-shaped device that appeared to be some kind of sensor. The robot rolled past me, its electric motor humming. I turned around and tailed the thing at a distance of fifteen feet.