anchor.diff:  
   (defclass font-app (base-app)
     ((font-loader :accessor font-loader)
  -   (bukva :accessor bukva)
  +   (bukva :accessor bukva :writer (setf bukva))
  +   (contours :accessor contours)
      (candidate :accessor candidate :initform '())))
   
   (defmethod setup ((app font-app))
  
positive.code: 
  (defmethod exit ((app font-app))
    (zpb-ttf:close-font-loader (font-loader app)))
  
  (defun start ()
    ;;setup drawing window
  
negative.code:     contours))
  
  (defun coords->curve (coords)
    "Coords is a list consiting of 3 control points, represented by x,y pairs. Returns an array of coordinates. Each coordinate is an array of x,y,z coordinates. Z is always zero."
    (make-array '(3 3) :initial-contents
  	      (loop for i below (- (length coords) 1) by 2
  		 collect (list (elt coords i) (elt coords (+ 1 i)) 0))))
  
  (defun evaluate (candidate target)
    ;;todo
    (zpb-ttf:do-contours (contour target)
      (zpb-ttf:do-contour-segments (start ctrl end) contour
  )))
  