如何在极轴扇区之间设置动画点？

I'm trying to animate a circle travelling on an arch around sectors in a polar graph (e.g. quarters of a circle, pie pieces). In the image below, the animation would move a single circle from point 1 to 2, then from 2 to 3, and so on until the circle travels from 5 to 6. I'm trying to animate a circle travelling on an