I was even able to re-create the von Koch snowflake code that was the starting point for this post:
drawLine() is a reasonable port of the original logo code and fractalLine() is a generalization that lets me illustrate the similarity between the von Koch snowflake and the peano curve.
The drawings do not animate yet... they're just a different api over the HTML5 canvas. But I'm frankly blown away at the ridiculous simplicity of the implementation: move() calculates the change in x and y by just taking the sine and cosine of the turtle's direction! So on top of the way turtles enable people to play with differential geometry (incredibly high-level mathematics made trivial by effective use of computing), the implementation is a beautiful application of very simple trigonometry -- a unit circle at work inside a simple state machine. There are some exciting lessons around an amazingly small amount of code... both in the von Koch and peano example and inside the turtle itself.
I think my next steps will be to create a player that will animate the drawing step-by-step and then to enable in-browser editing of the scripts. No idea when I'll be able to make time for either of those little projects. But this feels like a nice start.