I disagree. Because I can only sketch my part of the painting beforehand and try to anticipate what the therapist is going to do. Perhaps if I had a therapisty mind, there would be no surprises. However, despite my constant machinations aimed at dictating how our interaction will go, the result is never what I intended. So I can "sketch" beforehand all I like; but the therapist still affects the outcome - and sometimes it is unrecognizable from my imagined scene.