Thirty spokes converge on a hub
but it’s the emptiness
that makes a wheel work
pots are fashioned from clay
but it’s the hollow
that makes a pot work
windows and doors are carved for a house
but it’s the spaces
that make a house work
existence makes a thing useful
but nonexistence makes it work.
— Lao-tzu from ‘Taoteching: With Selected Commentaries from the Past 2,000 Years’, tr. from Chinese by Red Pine