How to Write a BANG Puzzle
(Work in progress... feel free to add, change, improve, etc.)
So you want to write a puzzle, eh? Simple! Create a simple substitution cipher, encode a crossword clue, and have the answer to that clue be the answer to the puzzle. Done.
Okay, so there can be a lot more to it than that. Team Snout has a page dedicated to the ins and outs of different puzzle designs from several different authors, as well as links to 8 years worth of advice from the GC Summit meetings. Included is a direct guide for writing puzzles, entitled "A Clue Design Primer." It is worth reading. \
Ian Tullis' talk "Advice From a Puzzle Snob" (and Larry Hosken's write-up) has a lot of information on what works and what doesn't in puzzle construction, from years of experience. It should be required viewing/reading before constructing any puzzle for the BANG.
The spark of creativity that blossoms into a puzzle can strike from many places. It's not as simple as "follow these steps". There may a statue at a location where the hunt is planned that makes you say, "I want to write a puzzle about that!" Or you may suddenly realize that a certain type of flower always has five petals, which could make for an interesting binary-encoded puzzle. Or you may think a puzzle that solves to "BANGLADESH" would be fun. From that initial inspiration, work out the other parts to make it a whole puzzle.
Look at the world around you and think, "How could I use this in a puzzle?" Most of the time, the answer will probably be "You can't", but from time to time, you'll notice an interesting pattern that can be used to make a great clue.
If you need a puzzle but can't come up with any ideas, consider using one of the basic puzzle types (crossword, word search, cryptogram, word jumble, etc.) and think of a way to put a twist on it. A word search without any words listed? A word jumble on a cube? Also, browse old BANG (and other puzzle event) puzzles or Games magazines and look for ideas to build on or twist to make your own puzzle.
 The Bare Bones
The overall guideline of your puzzle should be to provide a fun experience for your players. Generally, you need to start with three things to make an enjoyable BANG puzzle:
 1. The Answer
You'll need to know what solvers are working towards. If you don't know what the solution is going to be or what constraints the clue mechanism may place upon you, a placeholder answer works.
BANG puzzles originally solved to the location of the next puzzle ("BOWLING ALLEY ON FIFTH"). Later BANG puzzles solved to words or short phrases ("STRIKE" or "MAJOR LEAGUE UMPIRE"). This answer form acts as an access code that, when given to a hunt representative, reveals the location of the next puzzle. This format has been experimented with (long phrases, all locations available at the start, etc.), but the word or short phrase has become the gold standard.
 2. Content (aka The Data)
There are many ways to extract your solution from a puzzle, but you'll need something to extract it from. Anything that players can find patterns in can work here, as recognizing patterns is generally what is needed to solve a puzzle. This gives the puzzle designer a wide range of possibilities to work with. Text, pictures, physical objects, performances, games, interaction with GC, etc. are all fair and fun content to use in your puzzle.
Do not put content in a puzzle that will not aid in solving. Puzzle creators have put many things in their puzzles to make it pretty, more realistic, or just for fun. The problem is that the solver has no idea whether or not extraneous information is part of the puzzle. They may try to use something included only for decoration and end up very frustrated when they find out it wasn't necessary. A good BANG puzzle uses every piece of information presented in the puzzle, with nothing left over.
 3. The Mental Hurdle (aka The Aha or Eureka Moment)
In order for there to be a puzzle, there has to be something to solve. This usually means that there is an underlying pattern in the data presented. Figuring out this pattern gives players an "aha!" moment. Every puzzle has at least one aha; a BANG puzzle shouldn't have more than three. Using the pattern to convert the presented information to the answer is often called the extraction method. In other words, how do you get the answer from the seemingly random information?
 Fleshing It Out
With those three things, you may have a working puzzle, but only the bare bones of one. A simple cryptogram would work as a BANG puzzle, but there are two drawbacks: a) Most players have solved many such cryptograms before; and b) it will be a quick solve, especially with most players carrying smartphone with easy access to decrypting software.
 1. Theme it!
 2. Add a layer (or two)
 3. Leave internal hints (aka signposts)
 4. Make the players fill in the data
A classic way to add meat to a puzzle is to provide clues as to what the required data is, instead of actually giving it straight to the players. If teams are meant to deduce a pattern from a series of five-letter words, don't just give them the words, give them a one-removed reference to the word. A common way is to have crossword clues in a puzzle, which are fun and allows all team members to contribute. But it could also be synonyms, antonyms, word scrambles, hidden words, etc.
Now, meat and bones can make a good solid puzzle. Here are a few flavors to consider adding to the mix:
 1. Make it physical
A puzzle printed on paper is fine, but also something players can get from the newspaper or a magazine. BANGs tend to be more interactive, more similar to a short version of The Game than to the MIT Mystery Hunt. Try to find a way to bring the puzzle off the page. If you have a puzzle that involves a bunch of messages encoded using various Caesar's ciphers, you could put each message on a green strip of paper and put them all in a salad bowl, instead of just handing teams a printout. This give a nice visual appeal, as well as a clue as to what needs to be done to solve the puzzle.
 2. Use information from the location
Often called "environmental puzzles", they use information found around the location where the puzzle will be handed out. A statue, a placard, a bridge with 26 railings, a manhole cover with unusual words on it, a mural, a work of public art, the names of stores, etc. are all examples of environmental data that can be used in a clue. Just make sure that finding that information (aka data collection) is a fun process and not a boring drill.
 3. Appeal to the senses
Sight is the main sense used to get information from the puzzle to the brain. There are several others to consider mixing it up with. Sound-based puzzles are the second most used after sight and always worth considering. Using smells in a puzzle is perhaps the most tricky, and probably not the best option; not only are scents highly subjective, solvers may have allergies. Taste-based puzzle are less open to interpretation, especially if using really distinct flavors; however, allergies can still be a problem so be sure to warn players of possible allergens.
 4. Create a display
If your puzzle involves identifying pictures, bring real world samples of said items and make a display of it. Basically, instead of having ten pictures of fruit on a piece of paper, get those ten pieces of fruit and put them on a table in a way conducive to solving. Work on taking the player's eyes off the paper and into the real world. And, instead of having to make multiple copies of the information needed, you only have to make one and everyone can view it.
 5. Pretty it up
Like a gourmet dinner, the presentation is almost as important as the actual content. Little things like a logo, header, and/or footer consistent across the printed material makes it look professional. Use color where possible and will not result in a red herring. Use a font different from the standards. Make the font style match the theme of the clue. Consider binding for clues that last several pages.
 Dos and Don'ts
Unless you are somehow using these as intricate parts of the puzzle (and you probably shouldn't), some guidelines:
- DON'T include intentional red herrings. It's frustrating enough when solving and ending up going down your own wrong path. To find out that GC intentionally put a wrong path in their puzzle is maddening.
- DO make sure players know they've solved the clue. A recognizable word or phrase works best for this; a puzzle that solves to "X(1n0f1" or "disorbilivality" will have teams going back to see where they messed up. (Of course, if your BANG is scifi-themed, is about a robot named X(1n0f1, and includes a vocabulary list that defines "disorbilivality" as "the manner in which something is unable to orbilivate", then it may work.)
- DON'T make puzzles or experiences that only GC finds funny. Making teams sludge through cold mud to get the a clue may be funny to watch, but not to experience. "The challenge is not to amuse yourselves; it's to come up with something that 100+ people can all enjoy. Know your audience." - Team Snout
- DO make your puzzles and activities fun for the players.
- DON'T require a lot of obscure knowledge. If the average team has to use a smart phone to solve your puzzle, consider retooling it. They're no longer solving; they're researching.
- DO set aside your masterpiece puzzle if it's not working. It either needs to be rewritten, incorporated differently, or culled.
- DON'T make a puzzle harder. That is, once you've constructed a puzzle, don't try and make the crossword clues more obscure, for example. Adding an extra layer may work, just be careful.
- DO make your puzzles solvable by a majority of players. Aim for the average solver, not the elite teams.
- DON'T rely on hints or other external sources to overcome a puzzle's shortcomings.
There are a lot of tools out there to aid in constructing puzzles. Here's a sampler: