How are Patterns Described?

General idea... from Alexander

IF    you find yourself in CONTEXT
      for example EXAMPLES
      with PROBLEM
      entailing FORCES
THEN  for some REASONS
      apply DESIGN FORM AND/OR RULES
      to construct SOLUTION
      leading to NEW CONTEXT and OTHER PATTERNS
Graphical notations can help, expecially with showing relations among pattern objects/classes. But they are not sufficient.

We need to give several types of information about the problem domain, the forces acting in the sytem, and the resolution to which a pattern is to be applied.

This is not the only format used to describe design patterns but it is a popular one, from the GoF text.