anchor.diff:           (let ((event (event-key (get-event scr))))
              (if event
                  (case event
  -                 (:resize ;; if the scren is resized, relocate the window to the new center.
  +                 (:resize ;; if the screen is resized, relocate the window to the new center.
                             (move-window win (round (/ (height scr) 2)) (round (/ (width scr) 2)))
                             ;; better differentiation of types with methods.
                             (move win 0 0)
  
positive.code:                           while i do
                              (setf (value field3) i)
                              (draw form))))
  
        (if (edit form)
            ;; edit returned t, which means the user accepted the form
            (progn
  
negative.code:                             (let ((v1 (value field1))
                                    (v2 (value field2)))
                                (bt:make-thread (lambda ()
                                                  ;; simulate a long-running calculation running in a worker thread
                                                  (sleep 10)
                                                  (enqueue (concatenate 'string v1 " " v2) queue))))))
  
  