Minimal start: a very short HTML page that uses Proportion
Adding: using Proportion to make points, lines, and circles
Intersections: making points by instersecting lines and circles
Parametric: adding points on lines and circles
Parmetric spew: using parametric points to make many objects
Animating: motion from parametric points and a frame counter
Stress test: using "addClosestPointParam"
First and Second: naming intersections
Machines: many frequently-used constructions
Groups: organizing marks to use color, and a second animation style
Marks: making line segments and arcs
Lofting: filling areas betwen arcs and segments
Lofting: watch your parameter directions
Lofting tests test cases