Yes they are "french curves" made to "best fit" a curved line through "points" which cannot be defined as being a true arc (that is, having a common center point). Place the "french curve" along the set of "points" until as many points as possible line up with one of the edges on one of the selected "french curves" and "draw" the line. Of course if one of these won't work because you "points" are spaced further apart than would be encompased by one of the "french curves" you can always reach for that broken band saw blade and fit it through the "points" with the little lady's help. A plastic covered "lead snake" can also be found in the "sources" which will provide almost an infinite number of solutions, and "stay put" so you can have a "go / no go" look at your best fit before scribing the line.
steveo |