How this goes

Two arms, eight positions each. That's the whole alphabet.

• A message arrives letter by letter through your telescope. Tap the letter you believe you saw before your time runs out.
• Fog and failing light blur the arms. If you misread a letter, you won't know it — you'll simply send the wrong one.
• Once you've read the whole message, you set your own arms and send it onward, under the same clock.
• Your message then passes through other stations on its way to the coast. They have their own eyes, and their own fog.
• Nothing here fails you outright. A garbled message just keeps going — and the dispatch reads back whatever the chain, including you, made of it.
• Fourteen days, worsening weather, one crisis night.

The coast replies

Fourteen days kept.