What reason do you have for asserting that we can only draw straight lines or combinations of straight lines? I would think that there is no reason we cannot alter "left" and "right" motion at different rates to get a curve.The reason a perfect circle can never be drawn is because it would be a GIGAGON which is like a STOP sign (OCTAGON) with a billion sides. Each time you touch the pen to the paper you are drawing a straight line. A CURVE can not be drawn because it is constantly changing direction, so the least amount of width will make that portion of the curve a straight line. Ever notice when you enlarge a CURVE printed by any printer large enough you can see the gradiation of straight lines.