Chaos model

The chaos model notes that the phases of the life cycle apply to all levels of projects, from the whole project to individual lines of code.

Snippet from Wikipedia: Chaos model

In computing, the chaos model is a structure of software development. Its creator, who used the pseudonym L.B.S. Raccoon, noted that project management models such as the spiral model and waterfall model, while good at managing schedules and staff, didn't provide methods to fix bugs or solve other technical problems. At the same time, programming methodologies, while effective at fixing bugs and solving technical problems, do not help in managing deadlines or responding to customer requests. The structure attempts to bridge this gap. Chaos theory was used as a tool to help understand these issues.