Thanks, Rob, I am hoping Dave will jump in.
Don, I am looking for the methodology. I know what they look like. I have a defined distance and height. I need to know how to determine esthetically pleasing proportions of the convex and concave curves. Are they equal or some proportion of each other? Where is the center of circle the radius is taken from?
Example: If I drew an isosceles triangle, offset the edge of the base and the height, where along the new hypotenuse would the centers of the circle from whose ark I get the curve lie?