From the axles up, it was simply a pickup truck, albeit of the biggest and heaviest class: the kind that, on her visits back home, she saw driving around in farm country, carrying bags of cement and towing fifth-wheel trailers. From the axles down, though, it looked like nothing she’d ever seen. The wheels had been removed and replaced with contraptions that looked like miniature tank treads. At each corner of the vehicle, where her eye expected to see a round wheel, it was instead baffled by the impossible-looking spectacle of a large triangular object, consisting of a system of bright yellow levers and wheels circumscribed by a caterpillar tread made up of black rubber plates linked together into an endless conveyor belt about a foot and a half wide. This ran along the ground for several feet beneath each axle and then looped up and around the yellow framework that held it all together, which, she perceived, was bolted onto the truck’s axle using the same lug nut pattern as would be used to mount a conventional wheel. So it seemed that these things were a direct bolt-on replacement for conventional tires, made to spread the vehicle’s weight out over a much larger contact area. Just the thing for an environment that was covered with snow for six months out of each year, and mud for another two. And indeed as the day grew brighter, she saw that the truck’s rearview mirrors and upper body were spattered with dried mud. Conditions might be snowy up in this valley, but this truck had been stolen from some place where spring was well advanced.