Currently requires Chrome Canary 64.
Partial implementation is available to use angles (polar coordinates) as motion path.
Spec says containing box (here the
main element) should allow you to use a percentage length in
offset-distance, but currently requires fixed units and containing box has no effect.
Currently animating angle inside
offset-path (which rotates around the circle) and also the
offset-distance from 0 to 20vmin (which is the radius of the circle).
You can pause one of the animations to see only one at a time in the CSS Variables. Or change the anchor points to see how that affects the animation.