Christopher Alexander coined the term "PatternLanguage" to emphasize his belief that people had an innate ability for design that paralleled their ability to speak.

Chris's book A TimelessWayOfBuilding is the most instructive in describing his notion of a pattern language and its application to designing and building buildings and towns.

He defines a 'pattern' as a three part construct. First comes the 'context'; under what conditions does this pattern hold. Next are a 'system of forces'. In many ways it is natural to think of this as the 'problem' or 'goal'. The third part is the 'solution'; a configuration that balances the system of forces or solves the problems presented.

For an extensive example of the application of patterns, see Chris's other book A Pattern Language. Here he presents over 250 individual patterns that go into the making of successful towns and buildings (in the context of a western, even North American, environment).

To find out exactly what a pattern is, click on the tutorials below.

• Patterns and Software: Essential Concepts and Terminology
  A good introduction written by Brad Appleton
• Learning Guide To Design Patterns
  How to study and setup a group that studies Design Patterns, by Joshua Kerievsky.