The empty center

Thirty spokes start from the wheel axle,

but the spokes and axle do not make use of the wheel.

By mixing water, mud and earth we can shape a vase,

but water, mud and earth do not use the pot.

By opening up the space for the doors and windows, a room is built,

but the doors and windows do not make use of the room.

So consider what is useful as useless,

and the useless with the useful.