Coordination is about creating momentum.

By default, the sum of chaotic movement of components is zero.

No net motion of the system happens.

When you get some subset of the components even somewhat aligned, the force nets out to something non-zero.

That non-zero force points in a particular direction.

You get movement, slowly at first.

Components tend to swing to align with the direction of momentum each time step, in proportion to how much momentum there is.

The parts that aren't aligned either align themselves a bit more or drop out.

The parts that join are more likely to be pre-aligned.

So over enough time with some coherent, continued momentum no matter how misaligned originally you get alignment.

This means that alignment tends to beget more alignment over time.