(defvar *buffer* (make-rgb-pixel-buffer 10 10))
(fill-rgb-pixel-buffer *buffer* +white+)
(setf (rgb-pixel *buffer* 0 0) +red+)
(setf (rgb-pixel *buffer* 0 9) +red+)
(setf (rgb-pixel *buffer* 9 0) +red+)
(setf (rgb-pixel *buffer* 9 9) +red+)