Instead of designing a new kind of splines, I prefer use traditional B-splines and innovating “control points” and algorithms when you drag them — like dynamically updating the knot vector as well as control cage to make it more “smooth”. // @raphlinus
...is also *worth* exploring. I haven't had my coffee yet. In addition, I think thin plate splines (or perhaps some other RBF) are a very fruitful direction for controlling font variation. Piecewise linear is not smooth and doesn't do large numbers of dimensions well.