I've updated it with quad, cubic and sinusoidal modes. They all look good. Only problem is that because it's no longer linear, the various points can change at

I've updated it with quad, cubic and sinusoidal modes. They all look good. Only problem is that because it's no longer linear, the various points can change at different rates and thus create 'kinks' in the curve. When it's linear, the 'line points' and the associated 'control points' are always in a line locally tangential to the curve (don't know the proper terminology but hopefully you understand).