Thirty spokes are joined in the wheel's hub. The hole in the middle makes it useful.
You cannot receive what you don't give. Outflow determines inflow.
All things arise in unison. Thereby we see their return.
Pounding an edge to sharpness will not make it last.
I have no desire to desire, and people become like the uncarved wood by themselves.
To retreat after a work well done is Heaven's Way.