How are patterns represented?

• Through the use of the properties described in the previous slide 
  
  This is a common approach in books about Design Patterns. When you want to teach someone a design pattern, you need to give as much helpful information as possible. Unfortunately, this pattern representation is lengthy and requires a lot of reading. It is very difficult to find an appropriate pattern when you have to read description of every pattern.

• By utilizing diagrams or graphical representations
  
  "If you can't draw it it's not a pattern". Oftentimes the diagram is given as a way to visualize a pattern. Picture is worth a thousand words. It is very useful in object-oriented design to show patterns as diagrams because objects can easily be represented as geometric shapes. The draw back is the picture is not a substitute for a pattern description. You may identify the pattern that you already know from its diagram, but you will not be able to use it if all you have is a pictorial representation. And there are some cases when the diagram cannot be easily drawn for the pattern.

• Through the example
  
  Example is a natural way in explaining not just patterns but just about anything. Example is usually included with any good pattern definition. It might be difficult to determine what the problem is or which pattern it represents just by looking at the example. Still, example will let you see the solution to the similar problem and from that most people can determine the pattern right away.