From the Pollock Krasner House & Study Center web site:
In his barn studio, he spread his canvas on the floor and developed his compositions by working from all four sides, allowing the imagery to evolve spontaneously, without preconceptions. Pollock described this technique as "direct" painting and likened it to American Indian sand painting. He maintained, however, that the method was "a natural growth out of a need," and that its only importance was as "a means of arriving at a statement."
More here.
