But as he moved down the slope inside the cylindrical world, past the hotels and low-grav tourist shops, he leaned more and more heavily on the squat head of his robot companion. The two of them reached level ground, a loamy wilderness with solemn, ancient ranks of trees. The tub-shaped robot nurse nicked a quick blood sample from the nerveless flesh of Lindsay’s leg. As they shuffled along the leaf-strewn footpath, the machine fractionated the blood and mumbled over its data.