This paper presents the impact of clinical supervision on once-weekly psychoanalytically-informed training psychotherapy. The development of Oedipus complex theory is presented, culminating in Britton's work on the triangular space that opens up by working through the complex. The geometry of psychic space is described to highlight the importance of supervision, especially when training in therapy. The theme of spiders and cobwebs emerging from the clinical material provides a powerful metaphor for the tensions in psychic space. In the course of this training, the trainee therapist was at times less able to benefit fully from supervision, and thus the third position partially collapsed. Vignettes from anonymised clinical work are presented in the three ‘phases’ of this therapeutic process, illustrating the impact of the presence – and relative absence – of supervision.