We join spokes together in a wheel,

but it is the center hole

that makes a wagon move.

We shape clay into a pot

but it is the emptiness inside

that holds whatever we want.

We hammer wood for a house,

but it is the inner space

that makes it livable.

We work with being,

but non-being is what we use.

Tao Te Ching

Lao-Tzu