# Tackling the GCHQ 2021 Christmas Card!

Every year, one of the puzzliest challenges many solvers will encounter all year descends upon the world, as the GCHQ issue their Christmas card.

The GCHQ — or Government Communications Headquarters — provides security and intelligence services for the British government. Back when they were known as GC&CS — Government Code and Cypher School — they were responsible for funding Bletchley Park and its successes cracking the German “Enigma” code during World War II.

This year’s Christmas card was directed toward solvers with a secondary school education (essentially solvers age 11 and up), and was less complicated than offerings in previous years, but still offered an engaging challenge.

Here’s the link in case you’d like to try it for yourself.

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Last chance before we walk through the solution!

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Okay, ready? Good! Let’s do this!

Clue number one is an easy one, as you simply read the first letter of each word in the message. Your solution is CHRISTMAS.

Clue number two is a simple 4×4 across-and-down grid where 1-Across and 1-Down are the same word, 2-Across and 2-Down are the same word, and so on. The completed grid reads:

T H I S
H O O T
I O W A
S T A G

And the letters in THIS are highlighted in the grid, so the solution is THIS.

Clue number three is a complete-the-sequence puzzle where the names of the Hogwarts houses from Harry Potter are listed, but each house in the sequence has more letters missing from the beginning and end of the word. Slytherin is the missing house, and with three letters missing from the beginning and end of the word, your solution is THE.

Clue number four is a Blackout! or Minesweeper-style puzzle where you deduce the location of bombs in the grid according to numbers in the neighboring squares. Once you’re marked off each of the bombs, the remaining spaces form letters and spell out a word. Your solution is SAFE.

Clue number five is a mnemonic device, and solvers must puzzle out what chain of related words is represented by the device. In this case, the major taxonomic ranks that are used to organize related living things are represented, and the word Kindly points toward the second word in the taxonomic ranks, so your solution is Kingdom.

Clue number six has three overlapping circles, each with letters inside, and you have to figure out not only what the words are, but what missing six-letter word would sit in the middle of this Venn diagram.

I found this to be the hardest puzzle in the card by far, as I tried and failed in numerous attempts to anagram the letters into recognizable words. Finally, I decoded the shortest word — LEEDS — only because I remembered that this is a British organization and I have friends who live in Leeds.

Leeds led me to unraveling the other two answers — MANCHESTER and NEWCASTLE — and my meager knowledge of European football provided the missing six-letter word. The solution is UNITED.

Clue number seven is a simple cryptogram, and is quickly decoded to read “This is the 7th question: people born between nineteen forty-six and nineteen sixty-four are commonly known as baby what?”

The solution appears to be BOOMERS, but there is an additional instruction to follow after decoding the message, and you must encode the answer. Following the same letter-substitution rule, BOOMERS becomes KEEPING, and that is your solution.

Now each word must be placed in order on the tree for your message to properly read out.

• The word BABY in clue 7 points toward the stroller icon, so our message begins with KEEPING.
• The lightning bolt icon refers to Harry Potter, so the word THE from clue 3 goes next.
• The soccer ball icon points to clue 6, so the word UNITED continues the message.
• The word KINGDOM from clue 5 aligns with the crown icon, so that’s our fourth word.
• The lock icon is most closely associated with SAFE from clue 4, so that’s next.
• At first, I thought the image of the Stag was a Harry Potter reference, but I then realized that STAG was one of the answers in clue 2’s grid, so this was the place for THIS.
• Finally, the present is the perfect spot for clue 1’s solution, CHRISTMAS.

And the message is revealed, celebrating the mission of the GCHQ itself: Keeping the United Kingdom Safe This Christmas.

Did you unravel this festive puzzly challenge, fellow PuzzleNationers? Let us know in the comments section below! We’d love to hear from you.

Treat yourself to some delightful deals on puzzles. You can find them on the Home Screen for Daily POP Crosswords and Daily POP Word Search! Check them out!

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# Puzzle History: Codebreaking and the NSA, part 3

[Image courtesy of NSA’s official Twitter account.]

At the end of part 2 in our series, we left off during the early days of the NSA, as American cryptographers continued to labor under the shadow of the Black Friday change in Russian codes.

You may have noticed that part 2 got a little farther from puzzly topics than part 1, and there’s a reason for that. As the NSA evolved and grew, codebreaking was downplayed in favor of data acquisition. The reasons for this were twofold:

1. Context. You need to understand why given encrypted information is important in order to put it toward the best possible use. As Budiansky stated in part 1, “The top translators at Bletchley were intelligence officers first, who sifted myriad pieces to
assemble an insightful whole.”

2. Russian surveillance and bugging continued to grow more clever and sophisticated, pushing attention away from codebreaking. After all, what good is breaking codes or developing new ones if they can just steal unencrypted intel firsthand by monitoring
agents in the field?

Moving forward, the NSA would continue to pursue all manner of data mining, eventually leaving behind much of the codebreaking and analysis that originally formed the backbone of the organization. But that was in years to come. Cryptography was still a major player in NSA operations from the ’50s and onward.

[The progression of “secret” and “top secret” code words.
Image courtesy of NSA’s official Twitter account.]

In May 1956, NSA cryptanalytic veterans pushed a proposal titled “Recommendations for a Full-Scale Attack on the Russian High-Level Systems,” believing that specially designed computers from IBM could provide the key for cracking the impenetrable Russian cryptography wall. Some cryptographers believed that ever-increasing processor speeds would eventually outpace even sophisticated codes.

By 1960, the NSA had spent \$100 million on computers and analytical tools.

The problem? The NSA was collecting so much information that their increasingly small team of cryptoanalysts couldn’t dream of processing even a tiny portion of it.

But the quest for data access would only grow more ambitious.

In the wake of Sputnik’s launch in October of 1957, US signals intelligence would go where no man had gone before. The satellite GRAB, launched alongside Transit II-A in June of 1960, was supposedly meant to study cosmic radiation. (GRAB stood for Galactic Radiation and Background.)

[Image courtesy of NSA’s official Twitter account.]

But it was actually intended to collect radar signals from two Soviet air-defense systems. This was the next step of ELINT, electronic intelligence work. (The younger brother of SIGINT.)

The NSA would later find a huge supporter in President Lyndon Johnson, as the president was heavily invested in SIGINT, ELINT, and any other INTs he could access. This did little to quell the intelligence-gathering rivalry growing between the CIA and NSA.

Of course, that’s not to say that the NSA ceased to do any worthwhile work in codebreaking. Far from it, actually.

During the Vietnam War, NSA analysts pored over North Vietnamese signals, trying to uncover how enemy pilots managed to scramble and respond so quickly to many of the US’s airstrikes conducted during Operation Rolling Thunder.

Careful analysis revealed an aberrant character (in Morse code) in messages that appeared in North Vietnamese transmissions before 90 percent of the Rolling Thunder airstrikes. By identifying when the enemy used that aberrant character, the analysts
were able to warn US pilots whether they were heading toward a prepared enemy or an unsuspecting one during a given sortie.

Other NSA teams worked to protect US communications by playing the role of an enemy analyst. They would try to break US message encryptions and see how much they could learn from intercepted US signals. Identifying flaws in their own procedures — as well as members of the military who were cutting corners when it came to secured communications — helped to make US communications more secure.

[Image courtesy of NSA.gov.]

In 1979, Jack Gurin, the NSA’s Chief of Language Research, wrote an article in the NSA’s in-house publication Cryptolog, entitled “Let’s Not Forget Our Cryptologic Mission.” He believed much of the work done at the agency, and many of the people
hired, had strayed from the organization’s core mission.

The continued push for data acquisition over codebreaking analysis in the NSA led to other organizations picking up the slack. The FBI used (and continues to use) codebreakers and forensic accountants when dealing with encrypted logs from criminal organizations covering up money laundering, embezzlement, and other illegal activities.

And groups outside the government also made impressive gains in the field of encryption, among them IBM’s Thomas J. Watson Research Center, the Center for International Security and Arms Control, and even graduate student programs at universities like MIT and Stanford.

For instance, cryptographer Whitfield Diffie developed the concept of the asymmetric cipher. Joichi Ito explains it well in Whiplash:

Unlike any previously known code, asymmetric ciphers do not require the sender and receiver to have the same key. Instead, the sender (Alice) gives her public key to Bob, and Bob uses it to encrypt a message to Alice. She decrypts it using her private key. It no longer matters if Eve (who’s eavesdropping on their conversation) also has Alice’s public key, because the only thing she’ll be able to do with it is encrypt a message that only Alice can read.

This would lead to a team at MIT developing RSA, a technique that implemented Diffie’s asymmetric cipher concept. (It’s worth noting that RSA encryption is still used to this day.)

[Image courtesy of Campus Safety Magazine.com.]

The last big sea change in encryption came when the government and military realized they no longer had a monopoly on codebreaking technology. Increased reliance and awareness of the importance of computer programming, greater access to computers with impressive processing power, and a groundswell of support for privacy from prying government eyes, led to dual arms races: encryption and acquisition.

And this brings us to the modern day. The revelations wrought by Edward Snowden’s leak of NSA information revealed the incredible depth of government data mining and acquistion, leading some pundits to claim that the NSA is “the only part of government that actually listens.”

Whatever your feelings on Snowden’s actions or government surveillance, there is no doubt that the National Security Agency has grown and changed a great deal since the days of cracking the ENIGMA code or working with the crew at Bletchley Park.

Where will American codebreaking go next? Who knows? Perhaps quantum computing will bring codes so complicated they’ll be impenetrable.

All I know is… it’s part of puzzle history.

I hope you enjoyed this multi-part series on the history of 20th-century codebreaking in America. If you’d like to learn more, you can check out some of the valuable sources I consulted while working on these posts:

Code Warriors: NSA’s Codebreakers and the Secret Intelligence War Against the Soviet Union by Stephen Budiansky

Whiplash: How to Survive Our Faster Future by Joichi Ito

The Secret Lives of Codebreakers by Sinclair McKay

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# Puzzle History: Codebreaking and the NSA, part 2

[Image courtesy of NSA’s official Twitter account.]

At the end of part 1 of our look at the history of the NSA and American codebreaking, we left off with the pivotal Black Friday event.

On November 1, 1948, all intel coming from monitored Soviet signals went quiet. All traffic on military, naval, and police radio links was replaced with dummy messages. It was such an unprecedented and alarming event that London and Washington briefly considered that it might’ve been the first indication of preparations for war.

According to Code Warriors author Stephen Budiansky:

The full extent of the disaster only became apparent the following spring when real traffic started reappearing on the radio nets, now employing greatly improved — and completely unbreakable — technical and security procedures. The keying errors or other mistakes that had allowed most of the Soviets’ machine-enciphered military traffic to be routinely read by US and British codebreakers for the last several years had been corrected, and the much more disciplined systems that now replaced them slammed the cryptanalytic door shut.

Even the one-time pads that had offered some hope to attentive American codebreakers were updated, eliminating the ability to sort messages by which organization they originated from.

[The Kryptos sculpture outside CIA Headquarters. The NSA cracked
several of its codes before the CIA did. Image courtesy of Slate.com.]

The Office of Naval Intelligence wanted to take over from Signals Intelligence (SIGINT), demanding to see “everything” so they could do the job. They claimed SIGINT should limit their work to message translation, leaving interpretation to “the real experts.” This sort of territorial gamesmanship would continue to hamper government organizations for decades to come.

And that demand to see everything? That probably sounds familiar, in light of the revelations about government data collection and the PRISM program that were revealed in Edward Snowden’s leaks.

Black Friday was the start of all that, a shift from codecracking to the massive data collection and sifting operation that characterized the NSA for decades to come.

More amazingly, there was SO MUCH information collected during World War II that SIGINT was still poring over it all in 1949, decrypting what they could to reveal Soviet agents in the U.S. and England.

The fact that a high-ranking member of British Intelligence at the time, Kim Philby, was actually a Soviet double agent complicated things. After a decade under suspicion, Philby would flee to the Soviet Union in 1963, stunning many friends and colleagues who had believed in his innocence.

[The spy and defector, honored with a Soviet stamp.
Image courtesy of Britannica.com.]

Although the Russians had flummoxed SIGINT, other countries weren’t so lucky. The East German police continued to use ENIGMA codes as late as 1956. Many of the early successes in the Korean War were tied to important decryption and analysis work by SIGINT. Those successes slowed in July of 1951, when North Korea began mimicking Russia’s radio procedures, making it much harder to gain access to North Korean intel.

Finally, the chaotic scramble for control over signal-based data gathering and codebreaking between the government and the military resulted in the birth of the National Security Agency on November 4, 1952, by order of President Truman.

One of the first things the NSA did? Reclassify all sorts of material involving historical codebreaking, including books and papers dating back to the Civil War and even the American Revolution.

[The actual report that recommended the creation of the NSA.
Image courtesy of NSA’s official Twitter account.]

The creation of the NSA had finally, for a time at least, settled the issue of who was running the codebreaking and signals intelligence operation for the United States. And they were doing fine work refining the art of encryption, thanks to the work of minds like mathematician and cryptographer Claude Shannon.

One of Shannon’s insights was the inherent redundancy that is built into written language. Think of the rules of spelling, of syntax, of logical sentence progression. Those rules define the ways that letters are combined to form words (and those words form sentences, and those sentences form paragraphs, and so on).

The result? Well, if you know the end goal of the encoded string of characters is a functioning sentence in a given language, that helps narrow down the amount of possible information contained in that string. For instance, a pair of characters can’t be ANYTHING, because letter combinations like TD, ED, LY, OU, and ING are common, while combos like XR, QA, and BG are rare or impossible.

By programming codecracking computers to recognize some of these rules, analysts were developing the next generation of codebreakers.

Unfortunately, the Russian line was holding. The NSA’s failure to read much, if any, Soviet encrypted traffic since Black Friday was obviously becoming more than just a temporary setback.

Something fundamental had changed in the nature of the Russian cryptographic systems, and in the eyes of some scientific experts called in to assess the situation, the NSA had failed to keep up with the times.

I hope you’re enjoying this look at the early days of America’s 20th-century codebreaking efforts. Part 3 will continue next week, with the sea change from active codebreaking to data mining, plus Vietnam, the space race, and more!

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# Puzzle History: Codebreaking and the NSA

[Image courtesy of NSA.gov.]

The National Security Agency has been in the news a lot over the last few years.

It arguably all started with Edward Snowden and the revelations about government surveillance, both domestic and foreign, that emerged in his wake. Between President Trump’s intimations of Obama-era wiretapping (which also supposedly involved England’s GCHQ) and recent news stories about NSA contractor Reality Winner leaking information, the NSA continues to draw mainstream attention in the 24-hour news cycle.

When you factor in the declassification of codebreaking intel during and after World War II, we know more about the NSA’s inner workings than ever before.

You might be asking what the NSA has to do with puzzles. Well, everything. Because the NSA was born as a codecracking organization.

The NSA was founded in November of 1952, but its formative stages began during World War II, as codebreakers were recruited in the U.S. starting in 1943. Not only were they tasked with tackling the German ENIGMA code, but their secondary mission was to solve “the Russian problem.” This group was known as Signals Intelligence, or SIGINT.

William Friedman, one of the early figures in American codebreaking, described cryptanalysis as “a unique profession, demanding a peculiar kind of puzzle-solving mentality combined with patience. So staffing this new organization was a curious endeavor.”

Those who were recruited came from all walks of life:

Career officers and new draftees, young women math majors just out of Smith or Vassar, partners of white-shoe New York law firms, electrical engineers from MIT, the entire ship’s band from the battleship California after it was torpedoed by the Japanese in the attack on Pearl Harbor, winners of puzzle competitions, radio hobbyists, farm boys from Wisconsin, world-traveling ex-missionaries, and one of the World’s foremost experts on the cuneiform tablets of ancient Assyria.

A large campus was built that echoed the style and efforts of Britain’s Bletchley Park, including Alan Turing’s calculating machines, the bombes. Efforts on both sides of the Atlantic centered on cracking ENIGMA, the German codes used in all sorts of high-level communications. The teams worked alongside the bombes to try to determine which of the 456, 976 possible codes was being used in a given piece of communication.

It was a truly Herculean effort.

But while nearly half the staff focused on the Germans, others focused on cracking Russian codebooks, where words were translated into four-digit codes. Often, decrypting these codes involved “brute force” efforts, poring through numerous messages to pair up messages that used similar numerical groups, meaning they used the same cipher.

This would only work if the Soviets were lazy in their production of so-called “one-time pads,” encryption devices that had a particular code, which would be used once and then thrown away. Brute force codebreaking revealed that some of the one-time pads had been used more than once, a lapse in Soviet security that could work to the advantage of U.S. intelligence.

That deduction led to another stunning discovery: cracking the system used in encrypted messages to tell agents which encryption was used in a given missive. You see, each encoded message contained within it a code that dictated the cipher necessary to decrypt the message.

The Russians would later complicate this work by employing multiplexers: devices that would transmit numerous messages at once, making it harder to separate one message from another in the same dispatch.

[Image courtesy of Virtantiq.com.]

The Germans would unwittingly aid the US in their Russian codebreaking efforts when a POW camp in Bad Aibling, Germany, was captured by the US army, and they uncovered a German device designed to “de-multiplex” Russian messages. The device was called the HMFS, because Hartmehrfachfernschreiber, while a great deal of fun to type, is hard to say quickly.

After World War II ended, U.S. intelligence consolidated their efforts on “the Russian problem,” continuing their work unraveling the Russian codebooks. Slowly, the codemasters began determining which organizations in the Soviet government used which codes. Even if the codes weren’t broken yet, it helped the intelligence community organize and prioritize their efforts.

The problem? They had a very tight timeframe to work in. Those duplicated codebooks were produced during a very small window of time in 1942, and only issued to Soviet agents in the three years that followed. By 1947, SIGINT analysts knew the Soviets would soon run out of the duplicated pads. Once they did, those recurring patterns of encrypted numbers would stop, and the best chance for cracking the Soviet codes would be lost.

Still, there was reason to be encouraged. Some important code words had been identified. TYRE was New York City, SIDON was London, and CARTHAGE was Washington; ENORMOZ appeared often enough that they determined it referred to atomic bomb research in Los Alamos.

It would also be revealed, through careful analysis of decrypted intel, that Soviet agents were embedded in both the U.S. Justice Department and in England’s Bletchley Park campus. The Justice Department agent was identified and tried, but released after the court found insufficient evidence to place her under surveillance in the first place.

This was one consequence of the secrecy surrounding codebreaking: an unwillingness to reveal their codebreaking success by turning over evidence of it. (As for the Bletchley Park spies, one was identified in 1951 and confessed in 1964. The other was never identified.)

By this time, the Russians had gone over ENIGMA machines captured during the German retreat, and had unraveled not only how the devices worked, but how to improve upon them. This would lead to the next-generation Russian Fialka machine.

With ever-increasing complexity when it came to encryption, thanks to increased automation, codebreaking evolved into not just intelligence work, but intelligence analysis. After all, if you don’t know something is important, you don’t necessarily give it the attention it deserves. As researcher Stephen Budiansky put it, “The top translators at Bletchley were intelligence officers first, who sifted myriad pieces to assemble an insightful whole.”

It also led to bigger, faster machines, like Goldberg and Demon, two computation machines designed to more efficiently pore over the vast amount of encrypted information being intercepted by the various U.S. intelligence services.

In 1948, though, the game changed. It changed so dramatically that November 1, 1948, is still remembered in NSA circles as Black Friday.

I hope you’re enjoying this look at the early days of America’s codebreaking efforts. Part 2 will continue next week, with a look at the rise of the NSA, Cold War cryptography, and more!

[Quotes and certain photos were sourced from Code Warriors: NSA’s Codebreakers and the Secret Intelligence War Against the Soviet Union by Stephen Budiansky.]

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# The GCHQ Strikes Again!

Last year, one of the toughest puzzles I encountered all year was the GCHQ Christmas Card.

The GCHQ — Government Communications Headquarters — provides security and intelligence services for the British government. Back when they were known as GC&CS — Government Code and Cypher School — they were responsible for funding Bletchley Park and its successes cracking the German “Enigma” code during World War II.

And last Christmas, they released a puzzly Christmas card that challenged the staunchest puzzlers, with over 600,000 submissions, but only 3 successful solutions!

This puzzle is the first step in a larger event that the GCHQ expects will take MONTHS to solve. (Their official due date for submissions is February 28, 2017!)

The big change here is that instead of a series of webpages available free to the public, they’re releasing this puzzly master challenge as a book containing over 140 codes and puzzles.

But it’s for a good cause, as “all GCHQ’s proceeds from sales of the book will be donated to the Heads Together campaign, supported by HRH The Duchess of Cambridge, who wrote the foreword for The GCHQ Puzzle Book.”

The Duchess writes:

I have always been immensely proud of my grandmother, Valerie Glassborow, who worked at Bletchley Park during the Second World War. She and her twin sister, Mary, served with thousands of other young women as part of the great Allied effort to break enemy codes. They hardly ever talked about their wartime service, but we now know just how important the men and women of Bletchley Park were, as they tackled some of the hardest problems facing the country.

In a new century, their successors at GCHQ continue this intellectual tradition. Like their Bletchley predecessors, they have become well known for valuing and understanding the importance of mental wellbeing. This is so important when dealing with such discretion and the pressure which comes with this.

William, Harry and I are very grateful that this book is supporting our Heads Together Campaign. I hope it will not only amuse and challenge readers, but help to promote an open discussion of mental health problems, which can affect anyone, regardless of age or background. Together, we are aiming to change the national conversation around mental health from stigma and fear to openness and understanding. Those who buy this book and support the Heads Together campaign will be playing a part in helping people get the important mental health care they deserve.

Puzzles and charitable works: a perfect holiday match, to be sure.

For US shoppers, the book is available as a Kindle ebook through Amazon.com, but if you want a paperback copy, you’re better off ordering it from Amazon.co.uk. With shipping and conversion, it still cost me less than \$20.

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# Cracking the GCHQ Christmas Card!

As you may recall, my fellow puzzlers and PuzzleNationers, a few months ago, a government organization in England called the GCHQ — Government Communications Headquarters — released a puzzly Christmas card designed to tax even the savviest puzzle solvers.

They’ve finally released the answers to this mind-blowing series of puzzles, and I’d like to go over some of them with you. Partly to marvel at the puzzle wizardry necessary to solve this challenging holiday gift, and partly to gloat about the parts I managed to solve.

So let’s get to it!

Part 1 was a logic art puzzle where you have to deduce where to place black squares on an open grid in order to form a picture.

Each column and row has a series of numbers in it. These numbers represent runs of black squares in a row, so a 1 means there’s one black square followed by a blank square on either side and a 7 means 7 black squares together with a blank square on either side.

This is mostly a deduction puzzle — figuring out how to place all the strings of black squares with white spaces between them within the space allotted — but no image immediately emerged, which was frustrating. Once the three corner squares started to form though, I realized the answer was a QR code, and the puzzle started to come together nicely.

Part 2 was a series of six multiple-choice brain teasers. I’ll give you the first three questions, along with answers.

Q1. Which of these is not the odd one out?

A. STARLET
B. SONNET
C. SAFFRON
D. SHALLOT
E. TORRENT
F. SUGGEST

Now, if you stare at a list of words long enough, you can form your own patterns easily. Here’s the rationale the GCHQ used to eliminate the odd ones out:

STARLET is an odd one out because it does not contain a double letter.
SONNET is an odd one out because it has 6 letters rather than 7.
SAFFRON is an odd one out because it ends in N rather than T.
TORRENT is an odd one out because it starts with T rather than S.
SUGGEST is an odd one out because it is a verb rather than a noun.

Q2. What comes after GREEN, RED, BROWN, RED, BLUE, -, YELLOW, PINK?
A. RED
B. YELLOW
C. GREEN
D. BROWN
E. BLUE
F. PINK

After playing around with some associative patterns for a while, I realized that somehow these colors must equate to numbers. First I tried word lengths, but 5-3-5-3-4-___-6-4 didn’t make any sense to me. But then, it hit me: another time where colors and numbers mix.

Pool balls. Of course, the colors and numbers didn’t match, because this is a British puzzle, and they don’t play pool, they play snooker.

So the colored balls in snooker become the numbers 3, 1, 4, 1, 5, -, 2, 6. The numbers of Pi. And now the blank makes sense, because Pi reads 3.1415926, and there’s no 9 ball in snooker.

So the next number in the chain is 5, and 5 is the color BLUE.

Q3. Which is the odd one out?
A. MATURE
B. LOVE
C. WILDE
D. BUCKET
E. BECKHAM
F. SHAKA

This one came pretty quickly to me, as the names Oscar Wilde and Charlie Bucket leapt out. And if you follow the phonetic alphabet, you also get Victor Mature, Romeo Beckham, and Shaka Zulu. (I didn’t get Mike Love, however.)

Since Shaka Zulu was the only one where the phonetic alphabet word was the surname, not the first name, SHAKA is the odd one out.

(The other three questions included an encryption puzzle, a number pattern (or progressions puzzle), and a single-letter puzzle.)

Granted, since you could retake this part as many times as you wanted, you could luck your way through or brute force the game by trying every permutation. But managing to solve most of them made this part go much faster.

Part 3 consisted of word puzzles, and was easily my favorite section, because it played to some strengths of mine.

A. Complete the sequence:

Buck, Cod, Dahlia, Rook, Cuckoo, Rail, Haddock, ?

This sequence is a palindrome, so the missing word is CUB.

B. Sum:

pest + √(unfixed – riots) = ?

This one is a little more involved. To complete the formula, you need to figure out what numbers the words represent. And each word is an anagram of a French number. Which gives you:

sept + √(dix-neuf – trois) = ?

Dix-neuf is nineteen and trois is three, so that’s sixteen beneath a square root sign, which equals four. And sept (seven) plus four is eleven.

The French word for eleven is onze, and ZONE is the only anagram word that fits.

C. Samuel says: if agony is the opposite of denial, and witty is the opposite of tepid, then what is the opposite of smart?

This is a terrific brain teaser, because at first blush, it reads like nonsense, until suddenly it clicks. Samuel is Samuel Morse, so you need to use Morse Code to solve this one. I translated “agony” and tried reversing the pattern of dots and dashes, but that didn’t work.

As it turns out, you need to swap the dots and dashes, and that’s what makes “denial” read out. This also worked with “witty” and “tepid,” so when I tried it with “smart,” the opposite was OFTEN.

D. The answers to the following cryptic crossword clues are all words of the same length. We have provided the first four clues only. What is the seventh and last answer?

1. Withdraw as sailors hold festive sing-song
2. It receives a worker and returns a queen
3. Try and sing medley of violin parts
4. Fit for capture
5.
6.
7. ?

Now, I’m not a strong cryptic crossword solver, so this part took FOREVER. Let’s work through it one clue at a time.

1. Withdraw as sailors hold festive sing-song

The word WASSAIL both reads out in “withdraw as sailors hold” and means “festive sing-song.”

2. It receives a worker and returns a queen

The word ANTENNA both “receives” and is formed by “a worker” (ANT) and “returns a queen” (ANNE, reading backward).

3. Try and sing medley of violin parts

The word STRINGY is both an anagram of “try” and “sing” and a violin part (STRING).

4. Fit for capture

The word SEIZURE means both “fit” and “capture.”

WASSAIL
ANTENNA
STRINGY
SEIZURE

And with three more answers to go, it seemed only natural that three more seven-letter answers were forthcoming. Plus, when you read the words spelling out downward, you notice that the first four letters of WASSAIL, ANTENNA, STRINGY, and SEIZURE were spelling out.

If you follow that thought, you end up with the start of a 7×7 word square:

WASSAIL
ANTENNA
STRINGY
SEIZURE
ANNU___
INGR___
LAYE___

And the only seven-letter word starting with INGR that I could think of was INGRATE.

WASSAIL
ANTENNA
STRINGY
SEIZURE
ANNU_A_
INGRATE
LAYE_E_

And if the last word is LAYERED…

WASSAIL
ANTENNA
STRINGY
SEIZURE
ANNU_AR
INGRATE
LAYERED

Then the missing word must be ANNULAR. The original question asked for the last word though, so our answer is LAYERED.

This brings us to Part 4, Number Puzzles, where I must confess that I finally tapped out, because I could only figure out the first of the three progressions involved.

Fill in the missing numbers.

A. 2, 4, 8, 1, 3, 6, 18, 26, ?, 12, 24, 49, 89, 134, 378, 656, 117, 224, 548, 1456, 2912, 4934, 8868, 1771, 3543, …

B. -101250000, -1728000, -4900, 360, 675, 200, ?, …

C. 321, 444, 675, 680, 370, 268, 949, 206, 851, ?, …

In the first one, you’re simply multiplying by 2 as you go.

2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, and so on.

But you begin to exclude every other number as you move into double-digits, triple-digits, quadruple-digits, and beyond.

2, 4, 8, 16, 32, 64, 128, 256, 512, 1024, 2048, 4096, 8192, 16384, 32768, 65536, 131072, 262144, and so on.

But, as I said, I couldn’t crack the other two, and I’m already exhausted just running through these four sections!

And, based on the answers they released recently, Part 5 only got more mindbending from there.

As a matter of fact, not a single entrant managed to get every answer in Part 5 correct. Prizes were awarded to the three people who came closest however, and it turns out a staggering 30,000+ people made it to Part 5. Color me impressed!

This was, without a doubt, the most challenging puzzle suite I have ever seen, and I offer heartfelt kudos to anyone in the PuzzleNation Blog readership who even attempted it!

You’re welcome to try it out for yourself, though. I highly recommend using this link from The Telegraph, which allows you to skip to the next part if you get stumped.

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