a free slide editor where graphs and equations animate click by click

I make maths slides where the idea moves instead of sitting there. This one is a wheel rolling along a line to draw a cycloid, then three balls dropped from different heights on the same curve reaching the bottom together (the tautochrone). The slide is built in Tracé, which I made. The full editor is free and runs in the browser.

I would like feedback from people who teach: which topic would you animate first, and what stops you from using moving slides in class today?

https://traceanim.com/v/6r2bvY5NTvWI