Looping Trefoil Animation in After Effects

I need a looping animation of a stroke traveling along a trefoil. Please see attached image for concept. The darkest, green end is the head. The lightest, white or transparent end is the tail. The animation should just continuously loop. I need the final deliverable as an After Effects AEP file.

I've tried to follow tutorials myself but I couldn't it as I'm not an animator. It's probably not easy so please attempt only if you know what you are doing. Also please describe to me in words how you will do it. I will award the project to the person who can clearly communicate his plan and method.

In the event nobody can do it, I will accept a GIF made with a different animation program, along with the source file.

I need the animation in the following sizes:

64x64, 96x96, 128x128, 144x144