Benzoqunione pellets float at the air-water interface. Over time the pellets tend to converge near one another, creating the dynamic flock. Sub-figures show time-samples of the flock at (A) 0 seconds elapsed (B) 30 seconds elapsed (C) 60 seconds elapsed (D) 90 seconds elapsed (E) 120 seconds elapsed (F) 150 seconds elapsed (G) 180 seconds elapsed and (H) a close-up of the flock. Reprinted with permission from Satterwhite-Warden J. E., Kondepudi D. K., Dixon J. A., Rusling J. F., (2019) Thermal- and magnetic-sensitive particle flocking motion at the air-water interface. The Journal of Physical Chemistry B, 123, 3832–3840. Copyright 2019, American Chemical Society.