“This evening the Anthroposophical Society invited me to give a lecture about modern art, on 13 March. They start to wake up here [in the Netherlands].. .Please, tell me something, what I should emphasize, what you find most important. I shall also read something from 'The Spiritual in Art' by Kandinsky.. .But we still have other views on the whole, isn't it. I don't always agree with Kandinsky, and often more with your views. So please write a little much.. .You know, for me it is always easier to paint my principles. (translation from German, Fons Heijnsbroek, 2018)”