“But I do think that when people say 'a learning curve,' they make a mistake. Learning to me always seems to go in a straight, ignorant line and then, every so often, takes a jump straight upward.”

“Straight is the line of Duty, Curved is the line of Beauty, Follow the straight line, thou shall see. The curved line ever follow thee.”

“When a man in a forest thinks he is going forward in a straight line, in reality he is going in a circle, I did my best to go in a circle, hoping to go in a straight line.”

“If the old man looked at straight lines to keep his act together, I was going to stare at curved lines and go down in flames.”

“But if some mind very different from ours were to look upon some property of some curved line as we do on the evenness of a straight line, he would not recognize as such the evenness of a straight line; nor would he arrange the elements of his geometry according to that very different system, and would investigate quite other relationships as I have suggested in my notes. We fashion our geometry on the properties of a straight line because that seems to us to be the simplest of all. But really all lines that are continuous and of a uniform nature are just as simple as one another. Another kind of mind which might form an equally clear mental perception of some property of any one of these curves, as we do of the congruence of a straight line, might believe these curves to be the simplest of all, and from that property of these curves build up the elements of a very different geometry, referring all other curves to that one, just as we compare them to a straight line. Indeed, these minds, if they noticed and formed an extremely clear perception of some property of, say, the parabola, would not seek, as our geometers do, to rectify the parabola, they would endeavor, if one may coin the expression, to parabolify the straight line.”

“What is straight? A line can be straight, or a street, but the human heart, oh, no, it's curved like a road through mountains.”