I made animation demos:
The circle was meant to fill up without gaps, but it’s good enough for a proof of concept, and this way it’s actually much easier to see how I made it (8 rotating arcs rotating different numbers of degrees for different durations). Rotation goes around the midpoint so to make the arcs rotate around the circle I had to group them with a transparent circle and rotate that group. Keynote crashed 3-4 times while I was making this. Once I started saving every few steps it didn’t crash again lol.