It's fascinating watching a new complex codebase congeal on a team.

At the beginning in a code base everyone touches everything.

But over time people sort to the part they like best and it auto grows from there.

If they don't actively dislike that area enough to switch, they stay with it by default.

New people don't go into areas that are already well owned by default.

These are rules like "stay in alignment with the team's goals, avoid crowding neighbors, make sure every bit of code is covered."

You might recognize these as the three rules of bird flocking behavior.

Emergent order from three simple rules.

Beautiful.