"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."


Ursula K. Le Guin, 

Tao Te Ching (Book One, Chapter 11)