anchor.diff:        ;; Update angle fields
         (setf (@ ($ "#incidence") 0 inner-h-t-m-l) ((@ incidence to-string)))
         (setf (@ ($ "#rotation") 0 inner-h-t-m-l) ((@ rotation to-string)))
  -      (setf (@ ($ "#absorbed") 0 inner-h-t-m-l) ((@ absorbed to-string)))
  +      (let ((absorbed-html (@ ($ "#absorbed") 0)))
  +	(when absorbed-html
  +	  (setf (@ absorbed-html inner-h-t-m-l) ((@ absorbed to-string)))))
         ;; Update absorbed arrow
         ((@ absorb-arrow set-length) (* 10 (/ absorbed 100))))
   
       (defun calc-absorbed (incidence)
         "Calculate the absorbed percentage from the incidence angle"
  -      (abs (round (* 100 (cos (* incidence (/ pi 180)))))))
  +      (abs ((@ *math round10) (* 100 (cos (* incidence (/ pi 180)))) -1)))
   
       (defun up ()
         "Increment incidence"
  
positive.code:     (defvar tangential-arrow)
      ;; Acceleration
      (defvar time)
  
      (defun *stars ()
        (let ((g (new (3fn *geometry)))
  
negative.code: 	(setf (@ arrow visible) bool)))
      
      (defun arrows-visible (bool)
        (dolist (a (list normal-arrow incident-arrow tangential-arrow reflection-arrow absorb-arrow))
  	(arrow-visible a bool)))
      
      (defun update-tilt-direction ()
  