The Rule of Five

In the book there are several "Rules of Five" - handy - pun intended - ways to recall important tips or identifiers.

In breaking down the information and the processes into five basic elements - skills are learned faster.

One of the primary ones is based on the "Five Observables",

They are called the '5 observables' by a former Pentagon investigator, they include hypersonic speed, sharp turn movements, and the ability to fly without observable power or wings.  For more go to What are the Five Observables? | Five Observables