Hi.
I think it's easer to provide an example than to explain this step by step: https://drive.google.com/file/d/1L1rLVIod12stwSMm-BsSWRh5zlXtRYBB/view?usp=sharing But the basic idea is that you can create a classic tween with the desired duration, set the rotation of the tween to clockwise or counter clockwise, nest this animation in a Graphic symbol, and then create three keyframes for this parent symbol in the parent timeline. In the first span (between keyframes 1 and 2) you will set the parent Graphic symbol to play once and in tthe second span (between keyframes 2 and 3) you will set the parent Graphic symbol to play once in reverse. Please let us know if you have doubts.
Regards,
JC
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