anchor.diff:  
   [source,text]
   ----
  -scale(sequence(5,0,1), 10)
  +scale(10, sequence(5,0,1))
   ----
   
   Returns the following response:
  
positive.code: 
  We can manipulate arrays with functions.
  
  For example we can reverse and array with `rev` function.
  
  [source,text]
  ----
  
negative.code: 
  == Let
  
  The `let` function sets *variables* and runs a Streaming Expression that references the variables. The `let` funtion can be used to
  write small statistical programs.
  
  A *variable* can be set to the output of any Streaming Expression.
  
  Here is a very simple example:
  
  