A green bird darting in the night.
Will you be able to see it?
Will you be able to catch it?
Cling to Tao like a shadow.
Move without a shawdow.
Didn't he already go this concept with the crane being with the tao by standing patiently and waiting for the fish to swim by, catch and eat it? I'm not certain if all opportunities are there for the taking. His suggestion of going where the tao goes leaves one up for a bit of a roller coaster ride - no discernment. Just because it's a fish doesn't mean you have to eat it and just because you can doesn't mean you should. He has also gone over the fact that when you do make a decision you should leave no residue, no trace. So, by Day 58 he's already repeating himself, but just using different metaphors.