anchor.diff:  
   (defpackage :animation
  -  (:use :common-lisp :easing)
  +  (:use :common-lisp :cffi :wayland-server-core :easing)
     (:export
  +   initialize-animation
      animation
      sequential-animation
      parallel-animation
  
positive.code: |#
  
  ;; Improvement: maybe we should be able to pass &rest rest parameters to finished-fn
  (defmethod start-animation ((animation animation) &key (time (get-internal-real-time)) finished-fn (toplevel t))
    (setf (start-time animation) time)
    (setf (toplevel? animation) toplevel)
  
negative.code:    (integer? :accessor integer? :initarg :integer? :initform nil)
     (finished-fn :accessor finished-fn :initarg :finished-fn :initform nil)))
  
  (defun animation (&key target property from to (easing-fn 'easing:linear) (start-time 0) (duration 0) (toplevel? t) integer? finished-fn)
    (make-instance 'animation
  		 :target target
  		 :property property
  