Mysterious Triads

Photo date: February 12, 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 (among other persistent patterns) I got a pattern consisting of a row of three units: a small circular shape on the left, a large oval in the middle, and an oval or half-oval shape on the right.  Such a pattern persisted for hundreds of consecutive photos. Below are some examples.

At the 11:05 mark in the video below, you can see my camera viewfinder as I photographed the pattern above. What is interesting is that we can see the three-part pattern appear before our eyes from a simpler two-part pattern.