Principle for movements

Just arrived in Helsinki, Finland. It is much colder here than in Iceland yesterday. Checked into Scandic Hotel downtown. Had a brief private with Tomi after supper. Here are the main points on basic movements. I am trying to set the rules out for the initial Chen Style Taijiquan Practical Method workshop in Helsinki.
  1. Movement must contain two points.
  2. The two points must be on a line.
  3. The two points must be the longest in that particular set of action.
  4. The two points can only move away from each other, or into each other.
  5. All other parts of the body must go into or away from the line created by the two points. This means all other body parts must give way to the two-point line.
We worked a little in relation to the positive circle. Tomi is getting the idea and decided to go home to practice more. I will see him tomorrow morning to check on it.