The time was prearranged, though, obviously. If I set a time in the puzzle, Julie might double book while in the process of solving.
When picking a puzzle, it occurred to me that it might be fun to do it in characters, especially because this was something Julie already did sometimes for fun (don't you judge her!). I could present it as the government asking for help deciphering a vital secret message! Simple, classic, cheesy cloak-and-dagger excitement. The message could be written in a letter substitution cipher. Then again, it wouldn't fit the theme if the government needed some little code cracked with a pen and paper like a sudoku...
This reasoning went on for a while, but my end decision was to prepare a code that was far too complex for a human to break, but easy for a computer to break. I could suggest the right tool to use so that it was possible for Julie to actually break, and then let her find the location by following a very direct trail of breadcrumbs. It wouldn't really be a challenge, but unlike most puzzles, I needed to guarantee that it would be solved, and solved quickly.
She got the puzzle and set about it, but she missed my suggestion of how to solve it. I was seriously concerned that she'd misunderstand and think that I'd solved it by hand, when I hadn't. I'd just followed a set of instructions in a guide. But she did it.
You can read more at Julie's blog post here and Andrew's blog post here.
Curious about the ring? Here it is in all of its sparkly glory:
