theory
A clear positioning of Theo van Doesburg, that previous building styles must not have any influence on the architecture of the future. He expresses the idea that function determines the form of a building.
Architecture should open up, i.e. the construction should dissolve the boundary between inside and outside. This is achieved through large windows and doors, glass walls and large terraces, e.g. on the roofs.
All building elements of a house should have equal rights. That means, that the back of a house should receive as much attention as the front, and so on.
Inside, the architecture is the only plastic form, because paintings and sculptures are not allowed according to the author's views.
The English version.