I'm doing a weekly video with a given theme from School of Motion. This theme was opposites. I really pushed myself with the water aspect.
I really gave it a lot of thought. All of the opposites include:
-Circle/Square (which are 2D/3D)
-Lighter bounce v heavier bounce
-Rounded secondary animation v triangular
-And the animation loops, but the diagonal is facing opposite from beginning.
Also: Creative Dash supplied one of their project files: dribbble.com/shots/1944181-Loading?list=users&offset=5
Once I realized they were just animated masks on solid layers, it really made things less complicated for me. I just studied some videos of water, and animated some masks.