Many thanks to Remmij...
... who in a comment earlier this week correctly pointed out that GeoGebras ARE embeddable in regular web pages.
The links Remmij gave in the comments to Wednesday's post were exactly what we need to let us embed a GeoGebra interactive animation widget in your web page.
UNFORTUNATELY, because Blogger won't let me edit the header of this post, I can't embed it here in the regular SearchResearch post.
HOWEVER... I can embed it in an Interactive Distance to the Horizon page I'm hosting on my own website! Bummer that I can't put it into a blog post (but perhaps someone will show me how to do that as well).
When you click on that link, it will take you to this web page (illustration below) that's on my server, showing that you can in fact download the HTML and then edit it for whatever purposes you'd like.
Full credit where it's due: This interactive GeoGebra animation was created by Paul and is almost exactly what I was looking for. (He also did two more, including this Distance to Horizon, new and improved version which is really beautifully done.)
One of the nice things about GeoGebra is that you can see exactly how the animation was built, and can then change things to suit your own problem.
If you're a teacher (or just someone interested in understanding how things like this work), it might well be worth your time to built a simulation or two.
Back to our regularly schedule program next week.