A ball is constantly changing, rolling, acting. This is human life. Human beings never stop acting. Whatever you are doing - sitting, sleeping, even standing still - you are still acting. Without action, you do not exist. It is just like a ball that is constantly going here and there, or standing still in according to circumstances. When a slope comes, the ball rolls down the hill. It acts, but even thought it appears to be moving, the centre is always still. We call this stillness samadhi (single pointed focus, as on the breath).- Zen Master Dainin Katagiri, in Returning to Silence, comparing the meditative mind to the dynamic but still centre of a ball.
I was trying to think about that when my legs had fallen asleep so bad during zazen today that I couldn't even stand when I was done. I just rolled onto my side and laughed. I shook it out and eventually I could stand. Was pretty funny. I was told that laughing is extremely Zen. Especially at your self when things don't go as planned. So I guess meditation works. :)