JOI's father delivers the garage monologue (p. 160)
Son… son, you’ll have to put that what is that that Columbia Guide to Refractive Indices Second Edition down, son. Looks heavy anyway. A tendon-strainer. Fuck up your pronator teres and surrounding tendons before you even start.
Context
The boy has carried an optics reference book to his own first tennis lesson and won't put it down — the whole later career (weapons lenses, annular fusion, cinema) is in his hands in the garage, legible to the reader and invisible to the father, who sees only a tendon risk. The stammer ("that what is that that") is as written — the flask is doing its work.