How to read a ladder

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1. Columns are the parties. Time runs downward.
2. An arrow is one message. The label is the study claim, not a packet capture.
3. The moving dot is a reading aid. It is not traffic from a live system.
4. Emergency arrows stop on the voice platform.
5. The room diagrams are the 38 study-draft files. They were not redrawn from a fresh vendor doc.