"[after completing the ancestor puzzle] You have succeeded. I can feel the Ancestors' wisdom at work. Pay attention, for you will never see this revelation again. [the Ancestors reveal Sirrus' color marble code for the old Memory Chamber] The answer has been seen. There can be no turning back. Goodbye, traveller, until we journey together again."
January 1, 1970
https://en.wikiquote.org/wiki/Myst_IV%3A_Revelation