anchor.diff:          (cond ((> a 0) :positive)
                 ((< a 0) :negative)
                 (t :zero)))
  -  (assert-equal ____ c))
  +  (assert-equal :positive c))
  
positive.code:   (setf a 100)
    (setf b 23)
    (setf c 456)
    (let ((a 0)
          (b __)
          (c __))
      (assert-equal a 100)
      (assert-equal b 200)
      (assert-equal c "Jellyfish"))
    (let* ((a 0))
      (assert-equal a 121)
      (assert-equal b 200)
      (assert-equal c (+ a (/ b a)))))
  
negative.code: 
  (define-test test-limits-of-case
      "case is not suitable for all kinds of values, because
       it uses the function eql for comparisons. We will explore
       the implications of this in the equality-distinctions lesson"
    (let* ((name "John")
           (lastname (case name ("John" "Doe")
                                ("Max" "Mustermann")
                                (t "Anonymous"))))
    (assert-equal "Anonymous" lastname)))
  
  (define-test test-cond
      "cond is the general purpose form for checking multiple
  