The Book of Works
Dividing the work
Fences before fan-out: settle the shared contract, then let the parallel work run.
One machine is a colleague; several are a crew, and a crew without territories is a pile-up. The third law's floor version: before fanning work out, split it into pieces that do not share files, name what each worker owns and must not touch, and, above all, settle the shared contract, the interface everyone builds against, before anyone starts. Serial churn on a shared core mid-flight is how worker three quietly breaks what worker one shipped.
Then watch the seams, because that is where parallel work fails. The pieces each pass their own checks and disagree about the boundary: names drift, assumptions fork, two helpers do the same job differently. Integration is its own step with its own verification, and resources are seams too; two heavy jobs on one box starve each other into failures that look like bugs.
How to practice it
Contract first, fan-out second.
Freeze the shared interface before parallel work begins. Changing it mid-flight re-breaks every territory that already built on it.
Fence by name.
Name what each worker owns and what it must not touch. Written, explicit, per worker. An unfenced crew converges on the same file from different directions.
Verify the seams.
Each piece passing alone proves the pieces, not the whole. Budget a real integration pass where the boundaries meet.
Mind shared resources.
Memory, ports, rate limits, the working tree itself. Two jobs contending for one resource fail in ways that impersonate bugs.
Deep scripture: Codeuteronomy III — Large work is divided and fenced