Closing the session

1. Stop at 120 minutes total, whatever is unfinished. The per-entry times are caps for ending blind work and checking the solution, not promises you will finish.
2. Spend the 20-minute buffer in the plan's order: an unresolved core step first, then an unclear high-importance concept, then the buffer entry, then a closed-book reattempt.
3. For every entry you check, the note that matters is the precise obstacle — the wrong sample space, the missed tie case, the assumption you did not state.