There is a whole lot of interesting material about clothoid curves in Raph Levien’s PhD thesis http://www.levien.com/phd/phd.html http://www.levien.com/phd/phd.

There is a whole lot of interesting material about clothoid curves in Raph Levien’s PhD thesis http://www.levien.com/phd/phd.html http://www.levien.com/phd/phd.html Don’t be put off by the fact it’s a PhD thesis, a genre not generally noted for good clear writing. The tone is scholarly, but unusually readable, and there’s a surprising amount of well-researched historical material (chapters 5 and 6). He used a design tool based on these curves to design the popular open source monospaced font Inconsolata.