The Cowboy code, the first code in Secret Code Book, by Frances W. Keene.
Original uploader: "Sitting in Boise in a park with the girls, trying to figure out this puzzle box geocache so we can see what is inside. 5 Letter Answer." #IBGCp
How to Make a Cryptex: 15 Steps (with Pictures)
Scytale code -- wrap paper around paper towel roll.
What are puzzle ideas for real escape rooms? - Quora
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21 Escape Room Puzzles More
Escape Room Game Design Tips Part 1: Affordances and Signifiers | Secret City Adventures
Spy Secret Agent Birthday Party Invitations & by SIMONEmadeit
International Morse Code - Phonetic Alphabet