anchor.diff:          (pluck L2) ; 1st element of L2,
           (mix (cdr L2) (cdr L1)))))) ; remaining elements of both
   
  -(defun pluck (L)
  -  "Returns first element of list L as a one-element list or nil if L is empty"
  -
  -  (if (null L) nil ; ensures nil input returns 'nil not '(nil)
  -    (list (car L)))) ; first element of L as a list
   
   
   ;;; ----------
  
positive.code:       (if (atom (car x)) ; but first check if this element is an atom
          (append y (pluck x)) ; if it is, add it to the return list
          (append y (collect-atoms (car x) nil)))))) ; if it's not, search within it for atoms
  
  ;;; ----------
  ;;; Question 3
  
negative.code:   "Appends elements of list L alternatingly to the two sublists in list R"
  
    (if
      ;; Base Case
      (null L) R ; input list is empty
  
      ;; Recursion
  