Like the instructions say: you are playing iPod Submarine (original rules are here), a party game invented by Steve Dee in the wake of the Tham Luang cave rescue. For this puzzle, you’re playing an interactive version with Linus Pauling, John DeLorean, Ken Hakuta, Stephen Wolfram, and Richard Branson.

Gameplay almost exactly follows Dee’s rule sheet. You and four of the other players, chosen at random, see a six-word “problem”; the remaining player (never you) is shown only “Elon Musk,” and so has no idea what the problem is. Everyone must then submit a two-word solution. Everyone, including you, tries to guess which player was Musk. You will play two pointless-looking practice rounds, closely following the gameplay examples included in Steve Dee’s instructions. (Elon Musk’s first answer is always IPOD SUBMARINE, and his second is always SPACE ROADSTER.) Then you begin in earnest. Go ahead and play for a while. Restart and play again. What did you notice? There are two prominent-looking things you might want to investigate, corresponding to two gameplay challenges. (You can do the challenges in either order, but the order presented here is the most heavily clued.)

Challenge 1: Fool each of the nonplayer characters

The problems you’re presented with are not totally random. Read the first words of a series of problems and you’ll get an instruction for your first challenge. For example, maybe you saw:

• YOU NEVER GIVE ME YOUR MONEY
• WANT ACTUAL HEALTH AND SAFETY HUNT
• OTHER SIDE OF PILLOW NOT COOL
• PLAYERS TRAPPED IN MONSTERS ET MANUS
• IN BED ALREADY BUT BLADDER FULL
• ANY FANCY KETCHUP WORSE THAN HEINZ
• ORDER MIXUP BY ORDER OF MAGNITUDE
• INDIVIDUALLY WRAPPED TICTACS HARD TO OPEN
• "TO BLAVE" NOT ACTUALLY "TRUE LOVE"
• CALL QUEUE AT HEADQUARTERS IS EMPTY
• YOU PLAYED WITH FIRE, GOT TOAST
• MUSK OX LOOSE IN DORM ROOM

In that case, the first words have told you that YOU WANT OTHER PLAYERS IN ANY ORDER INDIVIDUALLY TO CALL YOU MUSK. The problem statements’ first words keep stating this goal, in various phrasings, over and over and over. OTHERS MUST FLAG YOU AS THE TUNNEL GUY ONE BY ONE. PLAY FIVE SEQUENTIAL GAMES EACH HAVING ONE OPPONENT PICK YOU AS THE CONTROVERSIAL ENTREPRENEUR. ONE AT A TIME MAKE ALL OTHER PLAYERS THINK YOU’RE THE PAYPAL BILLIONAIRE. And so on.

How do you do that, since random chance is not going to suffice? At the end of every round of the game, your five NPCs each announce which answer they thought was Musk’s. By observing and crafting test answers, you can figure out what they’re doing. (Note that your input words must occur in the dictionary (SOWPODS) or in previous play; the NPCs do not have to obey this constraint.) Then, in five consecutive rounds, craft an answer that triggers a different NPC, exactly one at a time. You don’t know what the other answers submitted are going to be, so a well-constructed answer may still be foiled by bad luck, but there’s no penalty for repeat tries.

NPC	Looks for the answer with . . .	Something like . . .
Richard Branson	The most instances of any one letter	BANANA TAPAS
John DeLorean	The greatest length difference between words	ABSENTMINDED NO
Ken Hakuta	The least alphabetical distance between initial letters	WACKY WALL
Linus Pauling	The most letters in common between the two words	GLEAN ANGLE
Stephen Wolfram	The highest SCRABBLE score	QUIZZER ALCOHOL

(Note that the name of each NPC satisfies his own desideratum.) As soon as you’ve successfully fooled the fifth NPC in a row, the next problem statement will be a clue.

• If the NPC challenge is the first challenge you’ve completed, you will be given the problem NPC CHALLENGE COMPLETED BUT PUZZLE UNSOLVED. That is a problem. The NPCs suggest some solutions: 1) SAME SESSION 2) APE MUSK 3) THRICE CONSECUTIVELY 4) CHECK WORDLIST 5) [player answer] 6) [Musk answer]. Onward to the Musk challenge!


• If the NPC challenge is the second challenge you’ve completed, you will be given instructions on extraction (see below).

Challenge 2: Mimic Musk

You may already have noticed that the “Elon Musk” answers are not random. Obviously the first Musk practice-round answer is always IPOD SUBMARINE, and his second is always SPACE ROADSTER. But once the game begins in earnest, the Musk answers are always drawn from the dictionary of answer-words in the game up to that point—and they’re drawn in a pattern. In the first round of the game proper, Musk always chooses the 5th and 12th words from his alphabetical list of words seen so far. In the second round he always chooses the 15th and 14th words in this list. In the third round he chooses the 13th and 21st words, then in the fourth the 19th and 11th. Then he repeats: 5, 12, 15, 14, 13, 21, 19, 11. That is, he’s spelling out ELON MUSK ELON MUSK ELON MUSK over and over.

Since you have access to the same wordlist, you can follow the hint and APE MUSK THRICE CONSECUTIVELY—i.e., supply three answers yourself in a row that match what the NPC assigned to be Musk would do. (You might want to do this early in the game, when Musk’s vocabulary is smallish and easy to keep track of, or you might do it very late, say a few hundred plays in, when the wordlist is big enough that the early stretch of Musk’s vocabulary will be pretty stable and you can almost certainly just mimic what he said four rounds ago.) When you do, the next problem statement will depend on what else you’ve accomplished in this session of the game.

• If the Musk challenge is the first challenge you’ve completed, you will be given the problem MUSK CHALLENGE COMPLETED BUT PUZZLE UNSOLVED. Again, the NPCs suggest some solutions: 1) SAME SESSION 2) READ CLOSELY 3) FIRST WORDS 4) PROBLEM STATEMENTS 5) [player answer] 6) [Musk answer]. Onward to the NPC challenge!


• If the mimicry challenge is the second challenge you’ve completed, you will be given instructions on extraction (see below).

Extract the answer

When you have (in the same game, in either order) solved both the NPC challenge and the Musk challenge, it’s time to extract an answer. It’s been hiding in plain sight, split up among answers submitted by NPCs in earlier rounds. At least, that will be true if the game has gone on a while; if you’ve been bashing away at it, then refreshed and sped through a new session, the relevant problem statement and answer sets may not have come up yet. In that case you will be asked to be patient—

It's time for the next round! The problem is BOTH CHALLENGES COMPLETED, ANSWER NEARLY ACCESSIBLE

The following answers were given: 1) KEEP PLAYING 2) ONE [or sometimes TWO] MORE 3) ALMOST THERE 4) HANG AROUND 5) NEARLY DONE 6) [player answer]

—while the program hastily serves up one or two problem statements whose answer set(s) you need.

Once you have access to all the needed answers, you get the problem statement BOTH CHALLENGES COMPLETED BUT ANSWER UNEXTRACTED. You won’t know what to submit as your answer, so make something up. When you do, you’ll see that the NPC answers are pointing you to the relevant words in the session so far:

The following answers were given: 1) [player answer] 2) EARLIEST APPEARANCES 3) PREVIOUS WORDS 4) WITH MOPECORE 5) WITH MAKE 6) GOOD JOB

That is, look back at your session log for the earliest appearances of MOPECORE and MAKE among the answers. Which word occurred WITH MOPECORE, and which occurred WITH MAKE? (The pointer words here will vary from session to session, depending on which problem statements you’ve seen.) In this example, the relevant NPC answers are INDUSTRIAL MOPECORE and MAKE WASTE, so your answer is INDUSTRIAL WASTE. In other games, you might see, e.g.,

It's time for the next round! The problem is BOTH CHALLENGES COMPLETED BUT ANSWER UNEXTRACTED

The following answers were given: 1) [player answer] 2) EARLIEST APPEARANCES 3) PREVIOUS WORDS 4) WITH VOLLEY 5) WITH ECCLESIASTICAL 6) WITH BANDWIDTH

leading you to INDUS VOLLEY, ECCLESIASTICAL TRIAL, and WASTE BANDWIDTH, again for an answer of INDUSTRIAL WASTE.

Once you’ve reached the BOTH CHALLENGES COMPLETED BUT ANSWER UNEXTRACTED problem statement, you’ll see that statement over and over again until you do what it suggests. If you give INDUSTRIAL WASTE as your answer to the problem statement, you get

The following answers were given: 1) INDUSTRIAL WASTE 2) THAT'S IT 3) CALL IN 4) THE ANSWER 5) PUZZLE SOLVED 6) WELL DONE

and the game will quit. Call in your answer. Congratulations! You’ve won iPod Submarine!