At the end of the 1950's and the beginning of the 1960's Appel had come to a free style, much more theatrical and espressionistic than his Cobra works and the works he made later on in the 1960's.
'I paint from the matter, because the matter appears to have as much possibilities as the mind, if not even more. It is an unpredictable energy wich can be transformed by contradictions and mingling. It is possible to make the presentation representable but also unpresentable'. (Alfred Frankenstein, Karel Appel, Amsterdam 1980, p. 60)