Rich has now organized our relatively-mature models into a Github repository. Let us know if you try them out! Details in the repository notes. https://github.com/whosawhatsis/Hacker-Calculus-models
We've updated the predator-prey time model to create a surface that can be viewed a little better than the previous model. You could turn the earlier model (Log #12) to do this, but we think the new one is more intuitive.
We encourage experimentation and the Github repository should facilitate that. Meanwhile work continues apace on our book and other ideas... stay tuned, and contact us via this site or Nonscriptum.com's "contact us" link if you have ideas.
We'll also be presenting this next week at the American Association for Advancement of Science (AAAS) Pacific Division Meeting in Pomona. On Friday Rich and I will be chairing a Scientific Maker event and Open Source Hardware Science Workshop - come on out if you are in the area. (Registration fee required.)