Accomplice!, the blizzard, and the Weston house — "When I looked down my own…"
When I looked down my own length, the glass’s round mouth was a narrow slot. This was because of my optical perspective. There was a concise term for optical perspective that I again could not quite make resolve. […] (specular is what refers to optical perspective; it came to me after I stopped trying to recall it)
Context
(Resolved again at pp. 954-955:) Hal running the father's optics vocabulary on his own supine sightline — the NASA glass on his chest as a lens problem — and the lexicon misfiring twice: the word that "comes to him" is specular (which refers to mirror-reflection, not perspective), and only later does he land on foreshortened. For the lexical prodigy (this same scene has him recalling an obsession sparked by "a titillating reference in the O.E.D."), watching the retrieval mechanism serve the wrong optics term and then a hedged "probably" is the DMZ-era erosion measured in the theme's own vocabulary (the wrongness of "specular" is our observation; the raw plays it straight — restraint noted). Foreshortening is also what this whole scene is, a man flat on the floor viewing his own length and his own family history at a distorting angle.