Two clinical examples are presented in order to demonstrate how the analyst uses what he perceives to be the patient's impact on his ability to think, in constructing an effective psychoanalytic working model. The two clinical cases, very different in character and in the countertransference difficulties they cause, lead to the construction of quite diverse working models, although an oedipal illusion plays a central role in both. The presentation is based on the premise that psychic space exists and that the shape of the psychic space of one individual affects by way of projection the shape of the psychic space of another. In the discussion the author traces Bion's concept of the working model and the abstractions which can be developed from it, as well as the use of Bion's theory in Britton's discovery of the effect that a patient's personal model of the oedipal situation can have on the mind of the analyst.