"Approximately 71 columns by 42 rows per panel" was derived from a hardcoded 8.4 px advance that nothing had measured. The measured advance is about 7.3 px, so the figure was roughly 13% short — a full-width pane on the reference display measures 140 columns, not 122. The paragraph now says the number is a consequence of the measurement rather than a property of the design. Co-Authored-By: Claude Opus 5 (1M context) <noreply@anthropic.com>