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 little circle above a big oval. The pattern started out as shown in the photos below.
Then the pattern started to get more complex, with an additional feature appearing on the right side of each orb.
At the 10:05 mark in the video below, you can see my camera viewfinder as I photographed the first pattern shown above.