As we indicated above that our work has been based on building extensions to Boehm's spiral model. This allows us to incorporate our aims of providing a reuse method which is integral to software development while supporting reuse continually and also encouraging a risk based approach to development. These extensions have taken the form of a 'reuse spiral'. This has a symbiotic relationship the spiral model; the spiral model encourages a risk based approach to development and the reuse spiral provides the 'know-how' for reuse. Thus the information which is collected by one of the spirals is used by the other and vice versa.
Each of the spirals of the two models are split into four quadrants. The activities that are concerned with these quadrants are as follows:
| Spiral model | Reuse spiral | Problems tackled |
| Q1 | ||
| Define system | Use information | Retrieval |
| objectives and | gathered as | |
| constraints | search criteria | |
| Q2 | ||
| Evaluate | Reuse risk | Evaluation |
| alternatives | assessment | Verification |
| identify and | information to | |
| resolve risks. | aid risk | |
| management | ||
| Q3 | ||
| Develop and | Reuse products | Development |
| verify next - | of previous | Modification |
| level product | developments | Integration |
| where possible | ||
| Q4 | ||
| Plan next | Focus record and | Storage |
| phases | commit decisions | |
| to the library |