The Connections categories of the seven-level words are as follows, in increasing order of difficulty:

Countries
Armenia, Denmark, Ecuador, Vietnam.

Chemical elements
arsenic, calcium, krypton, mercury.

Technically fruit
apricot, avocado, coconut, pumpkin.

Anagrams
camelid, claimed, decimal, medical.

Plausible cryptic crossword anagram indicators
diced up, ordered, sketchy, various.

Objects counted with -枚 in Japanese
acrylic, judo mat, seaweed, SIM card

1 across: Arsenic might be an essential trace nutrient

Arsenic is famously toxic, and was historically favoured as an assassination tool since it was hard to detect and mimicked the symptoms of cholera. But studies in rats, goats, and birds have demonstrated arsenic deficiency is possible when fed unnaturally low levels of the element. (Arsenic naturally occurs in groundwater at levels of a few parts per billion.)

17 across: Microsoft slang references an email system from the late 80s

Microsoft employees use “OOF” as shorthand for “out of office”, even though it doesn’t make sense as an acronym. Reportedly, it comes from the name of the auto-reply feature in a Xenix email system Microsoft hasn’t used since 1993.

25 across: Yuri Oganesson

Yuri Oganessian is a physicist whose discoveries were essential to the discovery of elements 106 to 118, and who led the international team in Dubna, Russia who first synthesized many of them.

The race for the periodic table is a fascinating story in its own right; the team at Lawrence Berkeley National Laboratory claimed to have first produced elements 116 and 118 in 1999, but the discovery was later exposed to have been based on data fabricated by Victor Ninov. Both elements were later synthesized for real in a collaboration between the Lawrence Livermore National Laboratory in the US and Oganessian’s Joint Institute for Nuclear Research in Russia.

Oganesson is the heaviest element synthesized to this date; only a handful of atoms have ever been produced. It sits at the bottom of the noble gases column on the periodic table, but it is theorized that it would actually be a reactive solid if it existed long enough for those to be meaningful descriptions.

39 across: Oxygen is sour stuff

The word “oxygen” is named by Antoine Lavoisier after the Greek word ὀξύς describing sharp or harsh tastes, since he believed (incorrectly) that it was a component of all acids. In German, the element is called Sauerstoff.

49 across: Ada Lovelace was Lord Byron’s daughter

Ada Lovelace is famous in computer science as the author of the first published computer algorithm (for Charles Babbage’s Analytical Engine) and the first person to recognize that the machine could have applications beyond calculation:

Again, it might act upon other things besides number, were objects found whose mutual fundamental relations could be expressed by those of the abstract science of operations, and which should be also susceptible of adaptations to the action of the operating notation and mechanism of the engine. Supposing, for instance, that the fundamental relations of pitched sounds in the science of harmony and of musical composition were susceptible of such expression and adaptations, the engine might compose elaborate and scientific pieces of music of any degree of complexity or extent.

Ada Augusta, Countess of Lovelace

Less well known is Ada’s relationship to Lord Byron, the eccentric poet and famous philanderer. Lady Byron believed her husband to be insane and left Lord Byron shortly after giving birth to Ada (the marriage lasted one year). She strongly encouraged Ada’s scientific and mathematical studies in the hopes that she wouldn’t take after her father.

52 across: Osu!!

Osu (押忍) is an informal acknowledgement mainly used by people involved in martial arts. It’s also associated with cheer squads, and is referenced in the Japanese title of the Nintendo DS rhythm game series known in the west as Elite Beat Agents. It’s believed to be an extreme contraction of oyahō gozaimasu (おはようございます), or “good morning”, with the kanji 押 (“push”) and 忍 (“endure”) having been assigned after-the-fact.

54 across: Falling coconuts don’t kill that many people

There is an urban legend that hundreds of people are killed by falling coconuts each year. That statistic is completely unsubstantiated, but there is a seed of truth to it: a 1984 paper by Dr Peter Barss reported nine cases of serious head injuries caused by falling coconuts in Papua New Guinea.

68 across: Europe’s spaceport is in South America

Here’s a great trivia question: with what country does France have the longest border with? Is it Spain? Germany? No — it’s Brazil. That’s because of French Guiana, an overseas department of France between Brazil and Suriname on the north coast of South America. It’s part of the EU and Eurozone but not the Schengen Area.

French Guiana’s location right next to the equator made it the perfect site for the Guiana Space Center, built in 1968 after Algeria won its independence from France. The spaceport is operated by the European Space Agency (ESA) and the French and EU space agencies. The space sector is a significant fraction of the Guianese economy.

69 across: The giant stones of Yap

Yap is an island in Micronesia famous for its inhabitants’ use of large stone disks as a medium of exchange for ceremonial gifts. Rai, as the stones are known to the northern Yapese, have their owners recorded in oral histories as they are impractical to physically transfer.

They are valuable in part because there’s no limestone on Yap; the stones were quarried on Palau and transported 400km by boat. Supply of rai greatly increased after European contact, as did the disks’ individual sizes, but production stopped with the arrival of the Japanese in 1914 and many were lost to typhoon and World War II.

1 down: Avocados probably did not coevolve with giant ground sloths

A paper from the 1980s suggested that avocados might have co-evolved with giant ground sloths, who were large enough to eat and scatter the large seeds. But more recent research has that’s probably not true: avocados were smaller before human cultivation, and giant ground sloths didn’t live anywhere near there anyways.

5 down: Ice is technically a mineral

A mineral is a substance that is

• naturally occuring
• inorganic
• homogenous
• solid
• has a definite chemical composition, and
• has a crystalline structure.

Glacier ice checks all those boxes.

In response, Hank Green hyperbolically exclaimed on TikTok: “Ice is a rock, water is lava, and you are a lava monster. I guess??“

24 down: Tatami mats are interesting mathematically

Ten years ago I wrote a post summarizing some of the math behind traditional tatami patterns, so go check that out.

47 down: The United States has a lot of biomes

Back in high school, I participated in the Great Canadian Geography Challenge, and this crossword clue is my favourite question from provincials that I still remember two decades later.

You can find a lot of different biomes in the United States: tundra and taiga in Alaska; tropical rainforests in Hawaii; and coniferous forests, broadleaf forests, desert, prairies, flooded grasslands, mangroves, subtropical grasslands, and shrublands in the contiguous states.

48 down: The Three Sisters

Corn, beans, and squash (including pumpkins) are the three sisters of North America. This nutritionally-complete combination of crops is key to the cuisine of indigenous peoples across the continent. They featured prominently in the myths and diet of the nations of the Haudenosaunee Confederacy, for example.

59 down: Legendre’s constant

In 1808 Adrien-Marie Legendre conjectured that the prime-counting function π(x) asymptotically behaves like

for some constant $B \approx 1.08366$. Decades later, it was proved that the conjecture was right but the constant was wrong — in fact, B is equal to exactly one.

Hilariously, the only known contemporaneous image of Legendre is a random watercolour caricature by Julien-Léopold Boilly.

61 down: The seconds pendulum was almost the definition of a meter

The meter was originally defined as one ten-millionth of distance from the North Pole to the Equator through Paris. The main competing proposal was to use the length of a pendulum with a period of two seconds.

By sheer coincidence, the two numbers are almost exactly the same — the seconds pendulum has a length of about 0.993 meters (plus or minus less than a centimeter, depending on where you are on the Earth).

The answer is RAGED, meaning “was inflamed”.

At first reading, it seems like this clue refers to the fiery Cinnabar Island Gym Leader Blaine from Pokémon Red and Blue, but the hidden real definition is only the last two words, “was inflamed”.

The remainder of the clue is wordplay that hints at the answer: “Cinnabar” means RED and “gym leader” can be interpreted as “the first letter of gym”, so “A gym leader in Cinnabar” reduces to “A G in RED” — hence, RAGED.

The answer is LEGENDS, which are “passed down through generations”. What do feet have to do with anything? Well, they’re LEG ENDS, of course…

An anagram of BIBAREL after removing the letter I (“destroyed one”), plus L (“pound”). The anagram indicator is “angry”.

Bibarel is a Pokémon in Pokémon Legends: Arceus.

A homophone of ale meant (“draught intended”). The homophone indicator is “received”.

The surface reading suggests an item like a Full Restore used in the Pokémon games to cure status conditions. The British spelling of draught/draft is partly in service of the surface reading; the influence of Harry Potter has made it more common in Canadian and American English when referring to potions and elixirs like those used in Pokémon.

Breaks down into GOOD (“well”), and D (“suited ultimately”, meaning the last letter of suited) after NATURE (“flora and fauna”).

Natures in Pokémon are characteristics that increase one stat at the expense of another stat. “Jolly” is a good nature to have for certain Pokémon on a competitive team.

The letter D (“disadvantage primarily”, meaning the first letter of disadvantage) following KIN (“lineage”).

Pokémon types have strengths and weaknesses against each other; for example water-types are good against fire-types and ground-types are not effective against flying-types. Because Pokémon evolutionary lineages tend to share types, they also tend to share their type advantages and disadvantages.

A charade of ALP (“peak”) and HA (“area”)

The surface reading suggests Mount Coronet, the dominant geographical feature of Hisui. The answer references Alpha Pokémon, larger- and stronger-than-normal Pokémon that serve as minibosses in Pokémon Legends: Arceus.

Pun on two definitions of grit.

Similar puns are present in Pokémon Legends: Arceus, as the items Grit Dust, Grit Gravel, Grit Pebble, and Grit Rock are used to raise Pokémon’s effort levels in a given stat.

An anagram of STONE surrounding (“catching”) the letters CH (abbreviating “child”). The anagram indicator is “tumble” although, as the question mark acknowledges, it’s slightly dubious to need to split apart a compound word in a cryptic clue.

A tumblestone is a raw material used when crafting Poké Balls to catch Pokémon with.

An anagram of A NAME IS. The anagram indicator is “confused”.

The character Ingo in Pokémon Legends: Arceus suffers from amnesia after being transported through time and space from the Unova region.

A charade of WAR (“battle”) and Y (abbreviating yes, a “decision”).

Trainer battles in Pokémon Legends: Arceus end with a stylized wordmark reading “Battle decided”.

Concealed in spookieST ARTifact.

Three artifacts — the Adamant Crystal, Lustrous Globe, and Griseous Core — are used to change the legendary Pokémon Dialga, Palkia, and Giratina into their Origin Formes. Of these, the one associated with the Ghost-type Giratina is probably the spookiest.

The letter E (“point”, as in the compass point east) repeated three times on either side of (“about”) P (“Pokémon starter”, meaning the first letter of Pokémon).

Cryptic definition — “Lustrous Globe” is just a funny way of saying “crystal ball”.

As mentioned above, the Lustrous Globe is a key item associated with the legendary Pokémon Palkia.

The letter E (“exclusive to begin with”, meaning the first letter of exclusive), then ADDITION (“supplement”) lacking the first two letters AD (meaning “announcement”).

Historically, Pokémon games have been released in groups of slightly different versions, such as Pokémon Red and Blue, Pokémon Gold and Silver, and Pokémon Diamond and Pearl. The primary difference between versions in the same generation are Pokémon that can be caught in one game but not the other; these Pokémon are referred to as version exclusives. Pokémon Legends: Arceus is somewhat unique in that it is not paired with a second version (or supplementary DLC), so there are no version exclusives getting in the way of catching ‘em all.

An anagram of PHIONE, then R (“rumour tip” meaning the first letter of rumour). The anagram indicator is “evolution”.

Phione is a semi-mythical Pokémon which can be bred from, but strangely does not evolve into, Manaphy. False rumours and urban legends were common in the early days of Pokémon before reliable and comprehensive sources of information developed on the internet.

The letter “A” is directly lifted from the clue, then DRAGON minus the first letter (“without a leader”). Aragon was a medieval kingdom that unified with Castile to form modern Spain.

Pokémon Legends: Arceus takes place in Hisui, a region loosely based on 19th-century Hokkaido. According to in-game legend, it was created by Arceus alongside the deities of time and space — which are revealed to actually be powerful Dragon-type Pokémon.

Pun — if a trick is a con, is the second time you do it a re-con?

The ultimate goal of Pokémon Legends: Arceus is to perform research tasks to collect information on all the Pokémon, which are compiled into the Pokédex.

Formed from the first letters of (“heads to”) Calm Lightning-Affected Nobles.

In the Pokémon Legends storyline, five “noble Pokémon” have become frenzied due to lightning-like energy from space-time rifts. The heads of the Diamond and Pearl Clans help you calm these nobles by providing you necessary items to set up boss battles.

Obtained from BEASTS by taking away the first and last letter (“coasts”).

The sun rises in the Cobalt Coastlands, so the “beasts” could refer to Purrloin, Murkrow, or the other Pokémon found in the approach to the shoreline.

Hidden (“part of”) beautifUL TRAdition.

The Ultra Ball is an improved version of the Poké Ball used for catching Pokémon.

Constructed from END (in the sense of goal or “mission”) inside the letters SE (“southeast”) and followed by the abbreviation R (“river”).

The surface reading could refer to Arezu or any of the NPCs who request your help in the Crimson Mirelands surrounding the rivers in southeast Hisui.

Double definition; can refer to moral lines or early TV.

The clue references the controversy over Pokémon Legends: Arceus’s somewhat dated-looking visuals. The answer references the fifth-generation games Pokémon Black and White.

Anagram of RARE ITEM TO LEVEL, after removing (“disregarding”) the letter O (“zero”) and one of the Es (short for “electricity”). The anagram indicator is “crafts”.

The main character in Pokémon Legends: Arceus is a time traveller, having fallen through a space-time rift to a world of the past. Item crafting is a mechanic in the game, although admittedly rare candies that raise a Pokémon’s level are not craftable.

Anagram of MAPS. The anagram indicator is “inaccurate”. Amps are a measure of electric current.

Because Pokémon Legends: Arceus takes place in the past, “current” maps of the Sinnoh region only vaguely resemble the regions depicted in the game.

Charade of DEC (the “last month” of the year) and OY (“expressing dismay”).

As mentioned in my introduction, I’ve been using Pokémon Legends: Arceus and cryptic crosswords like this one as a distraction from recent events.

The letter E (abbreviating “everyone”) in the middle (“entering”) of an anagram of STAB. The anagram indicator is “moves”.

In competitive Pokémon, STAB stands for same-type attack bonus, referring to the 1.5x damage boost moves get when used by a Pokémon of the same type. All else being equal, it’s better to use a STAB move than a non-STAB move, which helps when trying to predict what options an opposing trainer might select on their turn.

Obtained by deleting the odd-numbered characters of rAnDoM rIfTs.

The surface reading references the randomly-occurring space-time rifts that bring the main character (and others) to the setting of Pokémon Legends: Arceus. The main character briefly struggles to gain the acceptance of the people in Jubilife Village.

The letters GE (“glide vacantly”, meaning glide with its middle letters removed) set around SEE (“look”) spelled backwards (“up”, since this is a vertical clue).

The inclusion of ride Pokémon in Pokémon Legends: Arceus allows you to glide around, vacantly or otherwise, with the help of the flying-type Braviary.

The phrase A TAD (“vaguely” when used adverbially, as in a tad familiar), spelled backwards (“written up”, since this is a vertical clue).

The Pokédex is notoriously filled with vague and occasionally dubious descriptions that resemble Pliny the Elder’s writings more than it does a modern encyclopedia. The Pokédex in Pokémon Legends: Arceus is literally written up as a book.

A charade of the abbreviation RE: (“concerning”) and COIL (“loop”).

Several moves in Pokémon inflict recoil damage on the user. On the rare occasion when a battle devolves into a repetitive loop of healing and status moves, one of the combatants will eventually run out of available moves and use Struggle, which is one such move.

A charade of PAL (“friend”) and LID (“cap”).

This clue is a stretch to relate to Pokémon, but “friend cap” could be interpreted as referring to the limit of 6 Pokémon you can carry with you at a time. This limit feels less stringent than it does in other games, since it is easy to switch them out at the camps scattered across the region.

The end of valKYRIE. The Kyrie eleison is the common name of an important prayer in some Christian denominations.

The surface clue is suggestive of the legendary Zamazenta, the cover mascot of Pokémon Shield.

NO spelled backwards (“getting up”, since this is a vertical clue) after the latter half of meTAL.

The surface clue references the Pokémon attack Metal Claw.

Anagram of GLINT after removing L (standing for “loss”, so “lossless” suggests its removal). The anagram indicator is “variant”.

Shiny Pokémon are rare variants with unusual colours. When a Shiny Pokémon appears in the wild or from its Poké Ball, it is accompanied by a sound effect and a flash of light and stars.

The initialism PE (“training”, as in physical education) after (“under”, since this is a vertical clue) the letters L (short for “large”) and O (short for “officer”).

The surface clue refers to Zisu, the captain of the Galaxy Team Security Corps, who can be optionally battled at the training grounds.

Eagle-eyed solvers may notice the thematic message spelled out by the top and bottom rows of the puzzle: ARCEUS LEGEND.