anchor.diff:  
   (defun frame-files (directory)
     (directory (concatenate 'string directory "/*.pov")))
  +
  +(defun last-frame-number (files)
  +  (frame-number (car (last (sort-frames files)))))
   
   (defun animate-encode (&key
                            (directory *robray-tmp-directory*)
  
positive.code:                                     (frames-per-second *frames-per-second*)
                                      include)
    (ensure-directories-exist output-directory)
    (map nil #'delete-file (frame-files output-directory))
    ;; Write frames
    (loop
       for frame from frame-start
  
negative.code:                                     (output-directory *robray-tmp-directory*)
                                      ;(pov-file "frame")
                                      (frame-start 0)
                                      append
                                      (scene-graph *scene-graph*)
                                      (width *width*)
                                      (height *height*)
  