Spiro spline of Levien, perhaps an improvement to B-spline here

[stefano2734]

See Spiro spline of levien: also a part of bionic curves like matthek bionic curves
http://levien.com/spiro/
Inkscape does have a Spiro spline tool
In his phd he explains his spline in relation to other splines:
http://levien.com/phd/phd.html
http://levien.com/phd/thesis.pdf