We walked up to the Pont Melin-fach waterfalls in the Brecon Beacons. A pattern of bubbles was continually forming and dispersing below one of the falls. The bubbles formed along lines with voids between these strings of bubbles. This reminded me of the biggest structures in the Universe. Galaxies are known to form along strings called filaments with huge voids between. In other words, galaxies are not uniformly distributed in the Universe
https://en.wikipedia.org/wiki/Void_(astronomy)
