anchor.diff:      "The reduce function combines the elements
        of a list, from left to right, by applying
        a binary function to the list elements."
  -  (assert-equal ___  (reduce #'+ '(1 2 3 4)))
  -  (assert-equal ___ (reduce #'expt '(2 3 2))))
  +  (assert-equal 10  (reduce #'+ '(1 2 3 4)))
  +  (assert-equal 64 (reduce #'expt '(2 3 2))))
   
   
   (define-test test-reduce-right-to-left
  
positive.code:   (defun WRONG-FUNCTION-1 (&rest rest) '())
    (defun transpose (L) (apply #'mapcar (cons #'WRONG-FUNCTION-1 L)))
    (assert-equal '((1 4 7)
                    (2 5 8) 
                    (3 6 9)) 
                  (transpose '((1 2 3) 
                               (4 5 6) 
                               (7 8 9))))
    (assert-equal '(("these" "pretzels" "are")
                    ("making" "me" "thirsty"))
  
negative.code:     "mapcar and reduce are a powerful combination.
       insert the correct function names, instead of WRONG-FUNCTION-X
       to define an inner product."
    (defun inner (x y)
      (reduce #'WRONG-FUNCTION-2 (mapcar #'WRONG-FUNCTION-3 x y)))
    (assert-equal 32 (inner '(1 2 3) '(4 5 6)))
    (assert-equal 310 (inner '(10 20 30) '(4 3 7))))
  