I love the idea of somebody in 1944 (or now) hearing of a movie called CHRISTMAS HOLIDAY starring Deanna Durbin and Gene Kelly, thinking "That sounds like a heartwarming holiday romp," and being exposed to this: https://youtu.be/sBVWLwwkt3I #filmnoir#itsnotawonderfullife
Basic models of flocking behavior are controlled by three simple rules: 1) separation: avoid crowding neighbours (short range repulsion); 2) alignment: steer towards average heading of neighbors; 3) cohesion: steer towards average position of neighbors (long range attraction). With these three simple rules, the flock moves in an extremely realistic way.