Thirty auxiliaries are a hub, when there is none, there is a car.
埏埴 as a tool, when it is not, there is a tool for use.
The chisel is a room, and when it is not, there is a room.
Therefore, some are used for profit, and nothing is used.
Thirty spokes prop up the axle and act as an empty space for the wheel, so that the car can be used.
Containers are made out of clay, and with the emptiness of the containers, there are containers to use.
Doors and windows were dug to build a house, and when there was no space, there was a house to use.
Therefore, things that can be felt can make people convenient, and things that cannot be touched can be used by people.
Chapter 11 is simple and abstract, and the central argument is that what can be touched and what cannot be touched complement each other, and that the spokes make the wheels empty, which makes the car convenient. Containers made of clay have empty space to make containers available. Doors and windows allow the walls to have empty spaces, so that people can enter and exit freely, and there are rooms available.
It is this fiction and reality that constitute this world. Something real is something that we can actually feel or observe, in other words, something that modern science can explain. Imaginary things are things that we can't see or touch, and space is the easiest example to understand, so Lao Tzu uses space to describe "virtuality". In fact, space is between "virtual" and "real", so it is also best understood.
In other words, for the individual, "form" and "god" are equivalent to "reality" and "nothingness", and both are indispensable.
In fact, Lao Tzu's proposition is quite big, but in the end, it comes down to one place, focusing on the harmony of yin and yang.