It's the doctors or therapists office (in Austrian language), which is a space with a specific architecture and qualities, especially in Freud's ordination. It is still existing until this day, as a museum both in Vienna and in London, where the actual infamous divan is located.
I like that the term is connected or associated with the term subordination.
The Rhombus shape is a geometrical form that I use frequently in my work. I just learned that the rhombus shape actually is appearing often to patients that are schizophrenic, there are reddit subreads where people describe the appearance of this geometrical shape in times of psychosis or that this shape can trigger them into psychosis.