The New York Times is sending copyright takedown notices to developers who have created games similar to its popular Wordle puzzle, with the newspaper saying it is doing so to “defend its intellectual property rights.”

The New York Times’ letters, also called Digital Millennium Copyright Act (DMCA) takedown notices, were earlier reported by the tech journalism site 404. According to its reporting, the notices maintain The New York Times’ ownership of the game’s mechanics and concepts, such as its 5X6 grid and display of green tiles for correct letter guesses.

The newspaper’s copyright campaign comes two years after it bought Wordle from its creator, Josh Wardle, who created the word puzzle as a gift to his wife. Since then, Wordle, played by millions daily, has been included in the New York Times’ game package, which it includes as part of its subscription or can be bought separately for $50 a year. 

Some developers posted on social media that they received DMCA takedown notices this month for their Wordle-like games, with some describing the action as “sad” and “insanity.” One developer, Australian linguistics lecturer Jayden Macklin-Cordes, noted in a social media thread that Wordle was open-source when it first started, meaning the underlying computer code was available to everyone.

“One of the coolest aspects of the phenomenon was the proliferation of spinoff versions in all different languages and with independent, innovative twists,” wrote Macklin-Cordes, who developed an Australian version called AusErdle. He noted that he received a DMCA notice from the New York Times on March 7. 

“Regretfully, this means the end of AusErdle,” he added. “It’s sad that @nytimes hates harmless fun.”

Macklin-Cordes didn’t immediately return a request for comment.

Another developer of a Wordle clone using the African language Yorùbá described the takedown letter as “insanity,” noting that the New York Times doesn’t offer Wordle in other languages. 

In a statement to CBS MoneyWatch, the New York Times said it “has no issue with individuals creating similar word games that do not infringe The Times’s ‘Wordle’ trademarks or copyrighted gameplay.”

The newspaper said it “took action against a GitHub user and others who shared his code to defend its intellectual property rights in Wordle. The user created a ‘Wordle clone’ project that instructed others how to create a knockoff version of The Times’s Wordle game featuring many of the same copyrighted elements.”

It added, “As a result, hundreds of websites began popping up with knockoff ‘Wordle’ games that used The Times’s ‘Wordle’ trademark and copyrighted gameplay without authorization or permission. GitHub provided the user with an opportunity to alter his code and remove references to Wordle, but he declined.”

The New York Times didn’t identify the developer, but 404 notes that a coder called Chase Wackerfuss had created a Wordle-like game called Reactle. More than 1,900 versions were created using his code. 

In a message to CBS MoneyWatch, Wackerfuss said he took down the game after receiving the notice and has no plans to redevelop it. He also called the notice “disheartening” and pointed out that Reactle helped people learn software engineering or to create their own games. 

“I extend my sympathy to all developers and fans of the diverse games using Reactle,” he wrote. “The common thread was a shared intention to learn and have fun.