Answer to Question m20
    
    
    
    Incorrect. This definition of merge
    takes a different approach, using a loop.
    Suppose that A = [1,3,5] and B = [2,4,6].
    Here are the values of A, B and merge1 each time
    the beginning of the while-loop is reached, including
    the first time.
  A        B        merge1
  [1,3,5]  [2,4,6]  []
  [3,5]    [2,4,6]  [1]
  [3,5]    [4,6]    [2,1]
  [5]      [4,6]    [3,2,1]
  [5]      [6]      [4,3,2,1]
  []       [6]      [5,4,3,2,1]  
    Now the loop is done, and the function returns
    [5,4,3,2,1].  The correct answer is [1,2,3,4,5,6].