“We put thirty spokes together and call it a wheel; but it is on the space where there is nothing that the utility of the wheels depends. We turn clay to make a vessel; but it is on the space where there is nothing that the utility of the vessel depends. We pierce doors and windows to make a house; and it is on the space where there is nothing that the utility of the house depends. Therefore, just as we take advantage of what is, we should recognise the utility of what is not”

Lao Tze

can someone explain what this mean in simple language?
i don't understand...
the more i read the more blur i am =.=lll
LOL!