Until the French Revolution, messages could only be sent at the same speed as transportation. In 1792, Claude Chappe invented optical telegraphy, based on a series of geometrical figures created and retransmitted by the arms of his telegraph. The figures were associated with words and expressions, defined in a dictionary used both for transmitting and deciphering messages.
Form two teams and decide which one will send the first message. Each team goes to its platform. The team sending the message moves the articulated arms of the Chappe telegraph. The second team has to retranscribe the message and decipher it.