"What does the straight line mean to you?" I think you will ask.
It means several things. It symbolizes duty. It seems to have the quality of inexorableness that duty has. When I have something to do that must not be set aside, I feel as if I were going forward in a straight line, bound to arrive somewhere, or go on forever without swerving to the right or to the left.
That is what it means. To escape this moralizing you should ask, "How does the straight line feel?" It feels, as I suppose it looks, straight—a dull thought drawn out endlessly. Eloquence to the touch resides not in straight lines, but in unstraight lines, or in many curved and straight lines together. They appear and disappear, are now deep, now shallow, now broken off or lengthened or swelling. They rise and sink beneath my fingers, they are full of sudden starts and pauses, and their variety is inexhaustible and wonderful.