Thirty spokes share the wheel's hub; It is the center hole that makes it useful. Shape clay into a vessel; It is the space within that makes it useful. cut doors and windows for a room; It is the holes which make it useful. Therefore benefit comes from what is there; Usefulness from what is not there.
The use of not Thirty spokes meet in the hub. Where the wheel isn't is where it's useful. Hollowed out, clay makes a pot. Where the pot's not is where it's useful. Cut doors and windows to make a room. Where the room isn't, there's room for you. So the profit in what is is in the use of what isn't.
11. Tools Thirty spokes meet at a nave; Because of the hole we may use the wheel. Clay is moulded into a vessel; Because of the hollow we may use the cup. Walls are built around a hearth; Because of the doors we may use the house. Thus tools come from what exists, But use from what does not.