RE: [Demo notebook] Reference notebook: corrections and recurring beginner questions · RWI-21920

Case 39 — Crystal reflections: why a dark patch is not a coating test · source wording exercise

Reader check for “Crystal reflections: why a dark patch is not a coating test”: distinguish the discussion point “Compare multiple controlled angles and describe the visible observation without asserting…” from its proposed application. The thread offers a way to reason about the question, without adding a personal experience or a newly observed outcome. Review focus: source wording. Retain the source wording beside any paraphrase.