CHAPTER 52: Make competence reviewable

Boards: 52a and 52b.
Read the surrounding chapter before this lab. All examples are original and synthetic.

PREDICT
Use a pencil, the Chapter 49 files and the two boards. No additional program is required. Before looking at the answer, explain what happens to the September enquiry count when the order window extends through October.

RUN
From the companion root, run:
No code command is required. For the numerical cross-check: python visual_labs/ch49/walkthrough.py
Use python3 if that is your configured command.

COMPARE
Compare your written explanation with both boards and the worked answer below. Use actual project evidence rather than confidence or a course completion claim.

CHANGE ONE THING
Expected: enquiries remain 17; accepted orders rise to eight; buying enquiries rise to seven; revenue is EUR 4700 and contribution after marketing is EUR -720. Use the Chapter 49 visual lab to reproduce these values. Write a capability claim supported by source rows, a query, a check and an honest limitation. Explain what help you used.

EXPLAIN
State which input changed, which instruction handled that change, and why the resulting output is appropriate. If your prediction differs, identify the first step at which it diverges. Return to the surrounding lesson before adding more complexity.
