There are four seasons in each yearly cycle (spring, summer, fall and winter). In the Agile Software Development Life Cycle, there are 6 stages within each iteration ( plan, design, build, test, review and launch).
If you know how your application will look and function, then you can help in the planning and review phases of the agile life cycle.
As an example, think about software that has extensive and complex requirements based on permissions and user roles. The first iteration of the Agile SDLC releases an application that would allow for an administrator to create users. The second iteration applied roles and permissions based access. The third iteration integrated external data sources with use of API’s into the application.