Operation of a flip-flop memory. After colliding with the droplet in the bistable depression in the middle, the incoming droplet lands to the other possible position in the depression in an alternating manner. Thus, the triggered output alternates between the two output channels. Real time.

Note the (mostly) elastic collision; in a head-on collision of particles of equal mass, the incoming particle comes to rest, while the target is ejected at the same speed as the oncoming particle.