It may be useful to think of TiddlyWeb as a collection of pieces of Lego. Like Lego, there are types of pieces, some skinny, some fat, some curved, some straight, with different numbers of holes. And they all come in different colors. Similarly, in TiddlyWeb there are a small number of types of things, each of which comes in somewhat different forms. For most of these types it is possible for the administrator of a TiddlyWeb instance to add additional forms through configuration or plugins.

In TiddlyWeb the types are:

• store
  
• serializer
  
• handler
  
• challenger
  
• extractor
  
• validator
  
• filter
  
• middleware
  
• renderer
  
• twanager commands
  
  

Each of these parts can be extended to modify TiddlyWeb in ways simple or complicated. The individual pieces have simple behaviors, simple inputs and simple (as in easily described) outputs, but they can combine for complex behaviors. Much like a big box of black and white 2x6 Lego blocks, in the right hands, becomes an artistic masterpiece.