During his sporadic, Furious Muse–driven efforts to lose weight, he had been forcefully reminded of a basic fact of human physiology, which was that fat-burning metabolism just plain didn’t work as well as carbo-burning metabolism. It left you tired and slow and confused and dim-witted. It was only when he was really stupid and irritable—and, therefore, incapable of doing his job or enjoying his life—that he could be certain he was actually losing weight. So it was in that state that he began to shamble up the switchback trail. But even in his flabbergasted condition, he was soon able to pick up on a basic fact of switchback geometry that was about to become important. Two hikers who might be a mile apart from each other on the trail might nonetheless find themselves separated by only a hundred yards of straight-line distance as one zigged and the other zagged. Assuming that Jahandar was chasing them—which was what they had to assume—they might have started out with an excellent head start. And he hoped that they had preserved that head start by moving as fast as they were able. And yet the moment might come, a minute or an hour from now, when they might look down, and Jahandar might look up, and they might lock eyes on each other from a range that was easily within rifle, and maybe even within shotgun, distance.