One of the scary things about COVID-19 is how it spawns variants.

It’s a numbers game. If someone catches COVID-19, the virus replicates itself billions of times inside their body, and each replication offers the possibility for a mutation. Granted, most mutations don’t do anything to help the virus replicate. But eventually — boom — you get an Omnicron or a Delta.

I thought about this while watching the replication of another wildly successful virus: Wordle.

I’m being metaphorical here, of course. Worlde is a game, not a biological virus; and not only is it non-lethal, it’s totally delightful.

But! As an idea, a past-time, and a craze, Wordle has indeed spread like a wildfire from person to person. For its first six months of life, Wordle was a pure passion-project for its creator, who did no advertising. So the game spread entirely via word of mouth.

And Wordle has another viral quality that’s possibly even more interesting: It is spawning mutations.

Programmers keep on devising new variants — the same basic concept, but with small tweaks to the gameplay. One of the first ones I saw was Sweardle, where the word list consists only of four-letter curse words …

There’s a similar variant called Lewdle, with only sexually-suggestive words.

And then I saw Absurdle, where the word changes each time you guess, forcing you to slowly narrow it down until there’s only one possible word left from its 2,315-long word list …

Absurdle has a few other mutations that make the game less hellish: You have infinite guesses, and there’s a “give up” button that’ll show you the current answer when you’re at the end of your rope.

And then there’s Dordle, which requires you to guess two words at once, a pretty brutal task …

Want to enjoy Wordle gameplay but with … math? Then hie thee to Numble, where you have to guess a formula that’ll produce the target number …

These variants are only the tip of the iceberg! Others include Queerdle (the “yassification of Wordle”), Wheeldle (infinite guesses), Obscurdle (“you must determine the meanings of yellow and green squares yourself”), Primel (guess the prime number), Nerdle (another formula-guessing game), and more. There’s probably a new one being released even as I type this paragraph.

These games are all recognizably in the Linnaean taxonomy of Wordle, except with a few pieces of gameplay genetic-code swapped around.

The thing is, we could easily have predicted this viral evolution.

Video games have been evolving like this — copying the original hit, and introducing a small mutation — for years.

Back in the first burst of arcade games, any time there was a massive hit, people would do clones and copies, slightly changing the gameplay or the graphics to avoid getting sued. There were dozens of variants of Space Invaders and Galaxian — games where aliens zoomed down from above — and dozens of tweaked clones of Pac-Man, where you’d navigate a maze to gobble up items while being chased. And in previous centuries we saw the viral evolution of predigital games: Card games, board games and puzzle games would bite off each other’s style of play, introducing slightly different visual themes and gameplay variations. Copying has always been a sure route to success.

This makes sense, because as I’ve written before, popular new ideas rarely spring out of thin air. Most of the time they’re just a slight iteration on something which already exists, and which is already popular.

Slight viral mutations win in the world of biology — and they win in the world of culture. Wordle itself is a straight-up copy of pre-existing games like Lingo, Mastermind and Jotto, and it distinguished itself with a few clever mutations (free online, leisurely pace, one new word per day).

Indeed, when something is too new — culturally or technologically — it often dies because nobody can quite figure out what’s going on. The Segway died partly because it innovated too much at once: It deviated so radically from the typical ways of moving around. (Plus, it was evolutionarily “unfit”: It didn’t solve a real problem that anyone actually wrestled with.)

This is why sometimes the best way to come up with a new idea is usually to take something that exists and slightly change one aspect — or smoosh it together with another popular, existing concept.

That’s exactly what happened with this most recent variant of Wordle, Squabble …

It’s a multiplayer game with “Battle Royale” gameplay — so it is, in essence, a mashup of Fortnite with Wordle, much as the hit game Babble Royale mashes up Fortnite with Scrabble. (And hey: It’s worth noting that the very phrase “Battle Royale” — and its one-against-all gameplay mechanic — comes from the 1999 novel Battle Royale, which shows how mashups and mutations can cross genres, in a crude don’t-read-too-much-into-it analog to how biological viruses can jump between species.)

When you think about creation-by-mutation, we could thus probably predict new variants of Wordle that might emerge in the days to come, before the craze dies out.

What are the next ones, do you think?

Clive Thompson publishes on Medium three times a week; follow him here to get each post in your email — and if you’re not a Medium member, you can join here and some of your fees each month will support Clive’s writing!

Clive’s a contributing writer for the New York Times Magazine, a columnist for Wired and Smithsonian magazines, and a regular contributor to Mother Jones. He’s the author of Coders: The Making of a New Tribe and the Remaking of the World, and Smarter Than You Think: How Technology is Changing our Minds for the Better. He’s @pomeranian99 on Twitter and Instagram.