DURHAM, N.C. (WNCN)- If you spend time on social media, you may have seen your friends post a grouping of green, yellow, and black blocks.

The blocks show indicate how many tries it took them to guess a word from the puzzle game, Wordle.

The web-based game challenges players to guess the word of the day. The word of the day is not unique to a player, instead, everyone playing is trying to guess the same word.

Wordle’s downside is you can only play one puzzle a day.

Duke University Ph.D. candidate Devang Thakkar decided that was the one thing he’d change about the game.

“One day, I just missed it. I got busy and I didn’t get to do it. I was like, ‘how do I get back to it?’ That’s when I realized there was no way to get back to it,” he said.

Thakkar studies computational biology and bioinformatics with a focus on blood cancers.

He used this background to develop the website.

Taking his own data and open-source data from a similar word puzzle game, he was able to create a user-friendly interface. It only took him a weekend in January to create the site.

Click here to play archived puzzles.

“It was slow for the first few days but after that, it just ramped up a lot. I originally posted about it on Twitter and Reddit, and people just really liked it,” Thakkar said.

Thakkar said this week he had one million users play on his site in the last week for a total of about three million visits. He said he’s had friends text him to say their friends told them about the site.

“It was just meant to be a fun website for me and my friends. I was expecting a maximum of say, 100 people to use it but it’s insane how many people are using it these days,” he said.

For now, Thakkar doesn’t have any plans to create any other websites. He does enjoy board games and word games and plays them a lot in person.

Wordle was recently acquired by the New York Times.

The magazine places most of its games behind a paywall.

Wordle remains free for the time being.

Thakkar said he doesn’t expect the sale to impact his site right away. If a change does have to be made, he doesn’t expect it would change the experience for users.

“If it changes, I’ll have to figure out what to do with that, I might have to get a subscription and have a program that solves it every day, gets the word, and adds it to the archive,” Thakkar said.