Writing the 2021 CIA Murder Mystery Puzzlehunt
Earlier this year, I wrote a puzzlehunt for my college buggy team's annual Murder Mystery event.
If you want to jump right in, here is the starting page (the entire hunt is hosted as Google docs). It consists of four initial puzzles themed around the four major buggy roles (driver, pusher, mechanic, support), plus a final meta-puzzle tying them together. As mentioned, anyone should be able to solve these puzzles using the public cmubuggy.org and ciabuggy.org. However, it will be more fun if you have experience with buggy.
Traditionally this event is a potluck plus some simple puzzles and activities, but really just an excuse to see people dress up in formalwear. Due to COVID, in 2020 and 2021 the event was moved to a Zoom call; and in 2021, I finally had time to take a shot at writing more in-depth puzzles in the vein of Puzzle Hunt CMU. We also threw in some group social games, like "guess the average" and "recreate this photo", for free hints; you could also pay for hints by doing various physical challenges like planks or jumping jacks for our amusement.
My main goal for these puzzles was to be fun, buggy-themed, and fast enough for inexperienced puzzlers (most members) to solve in under two hours total. Fun and buggy-themed were mostly successful, while fast was mostly unsuccessful - we started with four teams of 4ish people each, and ended up merging three of them so they could catch up to the top team (and they still took longer than I expected). It's probably a common issue for first-time hunt writers, underestimating the hunt time. Overall, we got pretty good ratings in the feedback form responses; big shoutout to the main organizers Rachel and Sabrina, as well as playtesters Jean and Johnny.
SPOILERS AHEAD: I'm going to write up each puzzle and my thought process when writing them. If you'd like to solve the puzzles, I'd recommend doing that before reading any further. I'd expect it to take less than two hours for a single experienced puzzler.
The Most Dangerous Game
This is the first puzzle I wrote for the hunt. Ironically, it had the most playtesting and also the most complaints. The puzzle title is a reference to the Richard Connell short story as well as to the fact the clues are all from video games.
Each row in the table clues a weapon (specifically, a gun) from a video game. The highlighted section of the answer represents a part of that gun's name. The prices and conversion table provide an ordering.
| Price ($) | Short clue | Game | Gun |
|---|---|---|---|
| 4,750 | sniper rifle from popular FPS | Counter-Strike: Global Offensive / Valorant | AWP / OPerator |
| 6,500 | Mindrippers | Six Guns | Sanity's DEMISE |
| 12,000 | Bastok | Final Fantasy XI | FOURTH Division Gun |
| 24,300 | neither fish nor dogs | Watchdogs | Spear PhISH Sniper |
| 26,800 | potatoes, SPLAT | Splatoon 2 | GOO Tuber |
There's one odd row referring to sniper rifles in popular FPS games, that has two answers, with "OR" between them.
When you solve the clue, you end up with either "AWP" (from CS:GO) or "OPERATOR" (from Valorant).
This suggests that it's a "sounds-like" puzzle, which is further clued by the flavor text "I liked the sound of some of the options".
Put it all together and you get AWP/OP DEMISE FOURTH ISH OOT, which leads you to OPTIMIZE FOR THE CHUTE, a common joke phrase in buggy usually used to refer to asymmetrical designs that improve a buggy's performance in the tight "chute" turn.
However, there's one more layer of sounds-like to apply here to reach the final answer, OPTIMIZE FOR THE SHOOT - since they're all guns.
(The answer-checker for this hunt was to send me a Slack message, so I gently nudged "chute"-answerers over to my intended spelling).
In playtesting, we ran into the fact that while the title of this FFXI wiki page says "Fourth Gun", the actual name of the gun on the page is "Fourth Division Gun". So I swapped the clue's blank spaces to spell Fourth Division Gun instead, which led to the actual solvers being confused in the opposite direction (for like, way too long). In hindsight, maybe I should have just edited the wiki directly to fix it...
If I remember correctly, later on in the writing process I changed the solution from "optimized" to "optimize", which cleaned up a playtest complaint about a single "D" and also made letter counts line up better for the meta.
Drivers Office Hours
Sometime after I had written that first puzzle, Rachel and Sabrina scheduled the actual event. I realized that I needed to write way more puzzles, so I slammed out this simple one very quickly (and it was the fastest-solved puzzle, so that lines up). The puzzle title here is a reference to CIA office hours, which are study-hall / mentorship focused weekly events.
I wanted this puzzle to be something simple that everyone could contribute to, so there is a variety of topics across different fields. To thwart reverse image-searching, I hand-drew all of the images on my Remarkable 2 tablet.
Each diagram or formula clues a single letter, and the accompanying flavor text provides a number for ordering.
| Concept | Letter | Number |
|---|---|---|
| Glyphosate | P | First (1), we needed to roundup |
| Thermal diffusivity | A | got pretty heated for a second (2) |
| Brainfuck code | S | Then, I tried (3) to understand |
| Sforzando | S | played with even more fource (4) |
| Laffer curve | T | Nahyun's house, on Fifth (5) Avenue |
| Euler's number | E | working until like six (6) AM |
| Interphase | S | like seven (7) thousand phases |
| RC time constant | T | before we eight (8) dinner |
The resulting solution, PASS TEST is a reference to the buggy driver's "pass test" requirement to race, and also a reason to be studying.
Using "tried" to clue three (even in a computer science context) is definitely questionable, but the other numbers were obvious enough that it didn't matter for solvers. Also while playtesting, I discovered that there are sometimes alternative letters used in various contexts, like the Student's T-test equation, and removed them.
Loss of mass
For the flagging-themed puzzle, I considered the usual flag suspects - semaphore and naval signal flags - but those tend to be pretty boring ciphers, especially if you have a decoder handy. I spent some time trying to write an interactive Minesweeper, but kept running into the issue that you could brute-force mine positions by repeatedly dying; I think I could've work around this by writing several puzzle permutations and switching them every time you failed, but ultimately didn't want to spend the time on it (with less than a week to the event at this point).
Eventually I settled on the format of a nonogram with additional cluing in the Minesweeper number style (where the number shown indicates the number of mines in the adjacent eight tiles). This was neat, because it allowed me to write an otherwise-ambiguous nonogram, but clarify the ambiguities through the Minesweeper clues.
Marking the flagged mines / dark squares on the Minesweeper nonogram spells out bitmapped letters on an 8-by-4 grid for each letter.
The message spells SHOWPENNANTS, a reference to pennant flags, and also a homonym for "show penance", which matches the religious flavor text.
The title of this puzzle, "Loss of Mass", is also a reference to the buggy rule about intentionally changing the mass of your buggy (e.g., by tossing a sandbag onto it at the top of the freeroll for the additional gravitational potential energy, and dumping it before reaching the final uphill section).
A Team Effort
This pusher-themed puzzle is the last puzzle I wrote, with just a few days before the event. The title of the puzzle is a reference to buggy team entries - the top push team is the "A-team", then the "B-team", etc. - as well as the theme of the puzzle: the other independent buggy organizations at CMU.
Each clue in the puzzle describes a phrase where the first word in the phrase is the name of one of the independent buggy organizations. The fraternities were too hard to work in, and I couldn't figure out anything for Robobuggy either.
- Apex Predator
- Atlas Shrugged
- CIA Headquarters
- Fringe Benefits
- Spirited Away
- Sprint-Drag-Carry (SDC)
Taking the letters of the numbered blanks and ordering them produces the solution, SQUATTERSRIGHTS.
In hindsight, this is a relatively unsatisfying end to the puzzle - I should have made the solver "do it again", e.g. having the letters spell AGENT or FACTBOOK but making the solution have CIA tacked onto the front.
Oh well.
Final Puzzle: Closing Investigation Activity
I wrote the meta-puzzle last, which made things much harder. I would recommend not doing this.
At this point, I knew that some of the feeder puzzles were significantly easier than other puzzles, so I was wary of a format that could be solved without all the feeder solutions. As the flavor text suggests, this puzzle is a Caesar (shift) cipher puzzle, where each letter in each feeder solution is shifted by a different number.
This puzzle requires a little CIA knowledge: traditionally we refer to incomplete buggies only by a number - for example, during Emperor's build process, we referred to her as "Buggy #23"; in the following year for Aurora, #24. This number naming convention persists in places like the hardware storage cups, which are often labeled with the number alone.
At the time of this hunt, we had built exactly 25 buggies as listed on the CIA website, which was perfect - one number for any possible shift in the alphabet (with looping).
Each clue refers to a buggy's name, which is then transformed into the buggy number.
The buggy number then shifts the letter that many spaces in the alphabet (looping back around from Z to A, sometimes called "mod 26").
It's kind of lame to have to guess that you can loop back around, so I provided a Google sheets formula =if(regexmatch(H7, "[A-Z]"), if(code(H7) + I7 > 90, char(code(H7) + I7 - 26), char(code(H7) + I7)), "Error (use capital letters)") within the puzzle sheet itself.
Since the same buggies appear multiple times, this also gave me the freedom to write really stupid clues. For example:
| Buggy | Clue |
|---|---|
| Icarus | Flew too close to the sun |
| Icarus | 2017 doping documentary |
| Icarus | Palutena franchise, but kidn't |
This construction gave me sufficient freedom to just throw in the feeder answers (54 letters in all) and construct an equally-long answer that would satisfy the murder mystery: IT TURNS OUT THE REAL KILLER WAS THE BUGGIES WE BUILT ALONG THE WAY.
Overall, we got pretty good feedback on this hunt. I'd definitely like to write or contribute to another one in the future. Next time, I would probably start by coming up with a meta-puzzle mechanic first, and then designing the rest of the puzzles around it. I'd want to work with some other people with different strengths to get better variety with more logic-based and visual/non-word-based puzzles, since the puzzles I write skew towards wordplay. I'd also like to start earlier, do more playtesting, and host the puzzles on a website instead of Google Docs - either using the open-source CMU Puzzle Hunt server, or rolling my own static version to host with Github Pages.
As a final bonus, here's a poorly-written puzzle I wrote earlier this year, with a too-clever mechanic, that no one could test solve, even with hints. Maybe I'll re-work it eventually.
P.S. Yee Aun, I'll write your mass-balance puzzle someday...