Flock

Here is a flocking system where the white spheres are following the red one.
You can tweak the parameters and observe live what happens to the flock.

Center Weight - Force that attracts individuals to the center of the flock
Follow Weight - Force that attracts individuals to the target (the red sphere)
Velocity Weight - Adds a force depending on the velocity of all the other individuals of the flock
Separation Weight - Force that repulses the individuals to his neighbours
Random Weight - Add a random force