This is a continuation of "Cubic Bézier curves explained": http://scratch.mit.edu/projects/11771189/ The follow up is "Bézier curves and continuity explained": http://scratch.mit.edu/projects/11824563/
The recursion uses De Casteljau's algorithm to split a Bézier curve into two halves. The recursion ends when a curve is "flat enough". This is a scalable way to draw Bézier curves. Only the flatness decides how many line segments to be drawn. There are many references available, here is one: http://www.scratchapixel.com/lessons/3d-basic-lessons/lesson-11-rendering-the-teapot-bezier-surfaces/b-zier-curve/
