anchor.diff:  
   renders as:
   
  -[plantuml,_images/mydiagram,png]
  +[plantuml,_images/plantuml-demo,png]
   --
   class Car
   
  
positive.code: 
  renders as:
  
  [ditaa]
  ----
      +--------+   +-------+    +-------+
      |        | --+ ditaa +--> |       |
  
negative.code: For example:
  
  ....
  [ditaa,_images/ditaa-demo,png]
  ----
      +--------+   +-------+    +-------+
      |        | --+ ditaa +--> |       |
  