One method [of Jorn] was to work with accidental shapes, and this was to become a lifelong preoccupation. But in the beginning the techniques of Surrealism were put to good use: Collage, frottage, color sprayed on paper with an airbrush or floated on the surface of a bowl of water and lifted off on paper. Another way to break the link between line and plane was by what Arp called the "square-eyed" method or alternately, with Dali, putting one drawing on top of another, using transparent paper. Jorn had availed himself of all these methods and experiments by 1940.