Visual Metaphor

This is somewhat trifling but...New Year's Eve, waiting for my party to return from drink-retrieval, I played a very poor game of Millipede. Which I used to rock on NES emulator, but I had the excuse of playing impaired. Waiting for my plane to leave the gate several days later, I noticed that the heavy raindrops on the window would fall, gobble the ones below them, and leave a trail of new, smaller drops. Which randomized the pattern, but maintained an equilibrium density. I recalled that between levels in Millipede, there would be a rain of enemies that would do precisely the same thing, but leave trails of mushrooms. I thought for a few minutes about how this made the game seem poetic in an odd way.
The photo isn't mine. I entered 'rain on airplane window' into Flickr for the sake of illustration.