Patterns are a way of compressing information.

The CFEngine 3 language is made of promises and patterns;
it's about using patterns to create concise but powerful
promises. 

An example of a pattern in CFEngine is a list.  
You can have a list of things you want, or do not want:
for example, a list of packages that should be installed,
or processes that should NOT be running.

Implicit looping creates multiple promises that follow
the promise pattern.
