One of the curious customs to arise out of the Collapse was the practice of pyramiding robotic brain cases, in the same manner that certain ancient Asiatic barbarians raised pyramids of human heads that later turned to skulls, to commemorate a battle. While the brain-case custom is not universal, there is enough evidence from travelers' tales to show that it is practiced by many sedentary tribes. Nomadic peoples, as well, may have collections of brain cases, but these are not pyramided except on ceremonial occasions. Ordinarily they are stored in sacred chests which, when the band is on the march, are given positions of honor, carried in wagons at the head of the column.

Generally, it has been believed that this fascination with robotic brain cases may commemorate man's triumph over the machines But there is no undeniable evidence that this is so. It is possible that the symmetry of the cases may have an esthetic appeal quite apart from any other real or imagined significance. Or it may be that their preservation is an unconscious reaction to a symbolic permanence~ for of all things created by technological man, they are the most durable, being constructed of a magic metal that defies both time and weather.

— From Wilson's History of the End of Civilization

Thomas Cushing hoed potatoes all the afternoon, in the small patch on the bench above the river, between the river and the wall. The patch was doing well. If some unforeseen disease did not fasten on it, if it were not raided on some dark night by one of the tribes across the river, if no other evil fell upon it, come harvest time it would yield up many bushels. He had worked hard to produce that final harvest. He had crept on hands and knees between the rows, knocking potato beetles off the vines with a small stick he held in one hand and catching them as they fell in the bark container he held in the other hand.