"With regard to the diagonal, too, I am in complete agreement with you . As soon as it appears together with straight lines, I believe it should be condemned.. .A while back I started a thing entirely in diamonds like this . I have to find out if it's possible: intellectually I'm inclined to say it is. There's something to be said for the idea, because perpendicular and flat lines can be seen everywhere in nature; by using a diagonal line I would be canceling that out. But I'm inclined to say that this cannot be combined with perpendicular and flat lines or with different kinds of slanting lines."

“later Quote of Mondrian, about his 1890's; taken from 'Mondrian, Essays' by Piet Mondrian; Wittenborn-Schultz Inc., New York, 1945, p. 10; as cited in De Stijl 1917-1931 - The Dutch Contribution to Modern Art, by H.L.C. Jaffé; J.M. Meulenhoff, Amsterdam 1956, p. 39”

“To show that this end is only a beginning, it is essential that.. ..the series of galleries be followed by a room in which painting and sculpture will be realized by the interior itself.. ..demonstrating that what is lost for art is gained for life. This room could therefore be designed for use as a lecture room, a restaurant.. ..as a bar with an American jazz band.”

“It was during this early period of experiment that I first went to Paris. The time was around 1910 when Cubism was in its beginnings. I admired Matisse, Van Dongen and the other Fauves, but I was immediately drawn to the Cubists, especially to Picasso and Léger. Of all the abstractionists I felt that only the Cubists had discovered the right path; and, for a time, I was much influenced by them.”

“However, new plasticism is pure painting : the means of expression still are form and color, though these are completely interiorized; the straight line and flat color remain purely pictorial means of expression.”

“Culture produces relative consciousness of the changeable expression of reality. When this consciousness is attained, a revolt takes place: the beginning of the deliverance from that expression of reality. Destruction of its limitation follows. The culture of the intuitive faculties has conquered. A clearer perception of constant reality is possible. A new realism appears.”

“..the elements of form have a particular aspect; every fragment, every plane, every line has its proper character.”