Michael, I think I found a very minor "typo."
Comparing MarkCurveStart.js with MarkOpenCurveStart.js in Notepad++,
I noticed that the function name inside MarkCurveStart.js is "function MarkOpenCurveStart()".

Another note: Moved all SeiffertCurve script functions, except for the last .js function, from .js to .htm, as per your prior example with clothoid script.
The script seems to run much faster.
But when the script is open, changing an option caused color change of the sphere, as did subsequent mouse movement between option table and the screen.
Moved "g_style_index = 3;//reset color start index" to Update to correct the problem.

- Brian