anchor.diff:      "The mapcar function can be applied to
        more than one list. It applies a function
        to successive elements of the lists."
  -  (assert-equal ____ (mapcar #'* '(1 2 3) '(4 5 6)))
  -  (assert-equal ____ (mapcar #'list '("lisp" "are") '("koans" "fun"))))
  +  (assert-equal '(4 10 18) (mapcar #'* '(1 2 3) '(4 5 6)))
  +  (assert-equal '(("lisp" "koans") ("are" "fun")) (mapcar #'list '("lisp" "are") '("koans" "fun"))))
   
   
   (define-test test-transpose-using-mapcar
       "Replace the usage of WRONG-FUNCTION in 'transpose' with the
        correct lisp function (don't forget the #')."
     (defun WRONG-FUNCTION-1 (&rest rest) '())
  -  (defun transpose (L) (apply #'mapcar (cons #'WRONG-FUNCTION-1 L)))
  +  (defun transpose (L) (apply #'mapcar (cons #'list L)))
     (assert-equal '((1 4 7)
                     (2 5 8) 
                     (3 6 9)) 
  
positive.code:     "We can apply a function to each member
       of a list using mapcar."
    (defun times-two (x) (* x 2))
    (assert-equal ____ (mapcar #'times-two '(1 2 3)))
    (assert-equal ____ (mapcar #'first '((3 2 1) 
                                        ("little" "small" "tiny") 
                                        ("pigs" "hogs" "swine")))))
  
  
negative.code:     "The reduce function combines the elements
       of a list, from left to right, by applying
       a binary function to the list elements."
    (assert-equal 10  (reduce #'+ '(1 2 3 4)))
    (assert-equal 64 (reduce #'expt '(2 3 2))))
  
  
  (define-test test-reduce-right-to-left
      "The keyword :from-end allows us to apply
       reduce from right to left."
    (assert-equal 10 (reduce #'+ '(1 2 3 4) :from-end t))
    (assert-equal 512 (reduce #'expt '(2 3 2) :from-end t)))
  
  
  (define-test test-reduce-with-initial-value
      "We can supply an initial value to reduce."
    (assert-equal 1 (reduce #'expt '(10 21 34 43) :initial-value 1))
    (assert-equal 0 (reduce #'expt '(10 21 34 43) :initial-value 0)))
  
  
  (defun WRONG-FUNCTION-2 (a b) (+ a b))
  (defun WRONG-FUNCTION-3 (a b) (* a b))
  
  (define-test test-mapcar-and-reduce
      "mapcar and reduce are a powerful combination.
  