Two-Part Pattern Became a Three-Part Pattern

 Photo date: October 17, 2020. Photographer: Mark Mahin.   

I took the photos below while photographing only ordinary drops of pure, clean water falling in front of a black featureless background.  On this day I first got the two-part pattern shown below:

Then, as so often happens with these mysterious two-part patterns, the pattern grew more complex, and turned into a three-part pattern, as we below.