Then she understood that what she needed was the motion to a purpose, no matter how small or in what form, the sense of an activity going step by step to some chosen end across a span of time. The work of cooking a meal was like a closed circle, completed and gone, leading nowhere. But the work of building a path was a living sum, so that no day was left to die behind her, but each day contained all those that preceded it, each day acquired its immortality on every succeeding tomorrow. A circle, she thought, is the movement proper to physical nature, they say that there's nothing but circular motion in the inanimate universe around us, but the straight line is the badge of man, the straight line of a geometrical abstraction that makes roads, rails and bridges, the straight line that cuts the curving aimlessness of nature by a purposeful motion from a start to an end. The cooking of meals, she thought, is like the feeding of coal to an engine for the sake of a great run, but what would be the imbecile torture of coaling an engine that had no run to make? It is not proper for man's life to be a circle, she thought, or a string of circles dropping off like zeros behind him--man's life must be a straight line of motion from goal to farther goal, each leading to the next and to a single growing sum, like a journey down the track of a railroad, from station to station to--oh, stop it!