“The influence of my art is expressed in the movement of the Constructivists, of which I am the founder – Tatlin.”

Grosz and Heartfield, 1920: text on their billboard at the Dada fair in Berlin

As quoted in Modern Dancing and Dancers (1912) by John Ernest Crawford Flitch, p. 105.
Context: To seek in nature the fairest forms and to find the movement which expresses the soul of these forms — this is the art of the dancer. It is from nature alone that the dancer must draw his inspirations, in the same manner as the sculptor, with whom he has so many affinities. Rodin has said: "To produce good sculpture it is not necessary to copy the works of antiquity; it is necessary first of all to regard the works of nature, and to see in those of the classics only the method by which they have interpreted nature." Rodin is right; and in my art I have by no means copied, as has been supposed, the figures of Greek vases, friezes and paintings. From them I have learned to regard nature, and when certain of my movements recall the gestures that are seen in works of art, it is only because, like them, they are drawn from the grand natural source.
My inspiration has been drawn from trees, from waves, from clouds, from the sympathies that exist between passion and the storm, between gentleness and the soft breeze, and the like, and I always endeavour to put into my movements a little of that divine continuity which gives to the whole of nature its beauty and its life.

Richard Long (1982), cited in: Description of the exhibition Concentrations IX: Richard Long, March 31–July 8, 1984 at the Dallas Museum of Art http://texashistory.unt.edu/ark:/67531/metapth224905/m1/1/.
1980s

Quote in van Doesburg's unpublished writing: 'The struggle for the new', 1929-30; as quoted in Theo van Doesburg, Joost Baljeu, Studio Vista, London 1974, p. 187
Van Doesburg's quote is proposing here the sensuous-tactile expression of space as essential for modern architecture
1926 – 1931

Source: Night Watch

The Usurpation Of Language (1910)

translation from original Dutch: Fons Heijnsbroek
(original Dutch: tekst in circulaire van Charley Toorop, in het Nederlands:) De nieuwe vereeniging zal bestaan uit schilders, beeldhouwers en architecten. De oprichters stellen zich niet op het standpunt, dat het karakter der vereeniging door één enkele kunstrichting bepaald wordt. Zy gelooven dat voor iedere belangrijke uiting van deze tyd plaats is en bedoelen de nieuwe vereeniging als verzamelplaats voor de beste jonge kunstenaars, die gezamenlyk het karakter van de vereeniging bepalen.
text of Charley Toorop, in a circular for possible members of the new artist-society 'A.S.B.', Amsterdam 8 Dec. 1926; in the Archive J.J.P. Oud, Nederlands Architectuur museum, Rotterdam
before 1930

"Interview with Henri Matisse" by Jacques Guenne, L'Art Vivant (15 September 1925), translated by Jack Flam in Matisse on Art (1995)
1921 - 1940
Context: Slowly I discovered the secret of my art. It consists of a meditation on nature, on the expression of a dream which is always inspired by reality. With more involvement and regularity, I learned to push each study in a certain direction. Little by little the notion that painting is a means of expression asserted itself, and that one can express the same thing in several ways. Exactitude is not truth, Delacroix liked to say.

"Excerpts from the Teaching of Hans Hofmann", p. 66
Search for the Real and Other Essays (1948)