Thoughts Generated by a Daily Cup of Tao Post

I have recently started following other blogs and some of my favorites include Daily Cup of Tao, The Rambling Taoists, and Tiny Buddha, to name but a few.  Anyway, Daily Cup of Tao had a post yesterday which said, in part: "A hole in a wall is made of wall yet contains no wall" and that statement has popped up in my thoughts ever since I read it.  Just thought I'd share that for any who might be interested.  It fits with the wheel/hub metaphor for Dao, nothingness without which nothing is.