overlaying the points with parabolas? could you please explain in a little more detail how this proceedure works? what points did you choose as each group of three that would define the curve? using the straight edge to draw the curve -- does one form an angle based on the three points and draw lines from one side of the angle to the other allowing the tangents to form the curve or is there another (better) technique. i appreciate your patience in this for those of us who don't understand these kinds of things. thanks. j