The ternary process of designing a mechanism to carry out a given task is in three stages:

1. Start with a statement of ultimate purpose. Analyse this into a structure of purposes and sub-purposes. If a version of the task, or the work, already exists, then analyse it and map its tertiary structure.

2. Impress this tertiary structure on a kinematic graph ensuring that it will act so as to express the purposes. This yields the secondary structure.

3. Devise a primary structure, the causal activity of which will express the secondary structure required.

In brief, start with your purposes fully understood, then construct a ternary mechanism to express them.