sentence diagram

Then teacher would draw lines that tied various parts of her sentence together, “at the door” descending like a staircase from its noun. This moment made me happy. I was perhaps the only student in the class who relished diagramming; who could while away a happy hour picturing predicates docking at the ports of their subjects like ships. Levels one through six were called grammar schools then, attesting to the importance once placed upon the subject.

—William Gass, “The Aesthetic Structure of the Sentence,” Life Sentences: Literary Judgements and Accounts (Alfred A. Knopf, 2012)