doodle
A drawing or doodle can be said to be endogenetic if it does not depict an external object, but is rather the projection of a fictive entity produced by the writing (the layout of an imaginary town–Yonville, for example–where the action of the novel unfolds; a person’s features; the spatiotemporal schema of an action; an invented object; and so on).
(Biasi 1996, 43)