(defun boolean-values (n &aux (result '((t) (nil))) (new-result '()))
  (dotimes (i (1- n) result)
    (dolist (thing result)
      (push (cons nil thing) new-result)
      (push (cons t thing) new-result))
    (setf result new-result
          new-result '())))



CL-USER> (boolean-values 3)
((T NIL T) (NIL NIL T) (T T T) (NIL T T)
 (T NIL NIL) (NIL NIL NIL) (T T NIL) (NIL T NIL))