When U.S. Education Secretary Betsy DeVos proclaimed in a major speech Tuesday that “Common Core is a disaster” and “dead” at the federal education department, something stirred in Noah Mackert.

Mackert, a former New York City educator now living in Massachusetts, recalled that the standards had prompted anything but a disaster at his school after New York rolled them out in 2011. So he took to Twitter to share the story of what it was like when Democracy Prep, the charter network where he worked and now consults, made the transition.

“I know that many Americans on the right and the left have negative associations with the phrase ‘Common Core,’ even if they’ve never seen the standards,” Mackert told Chalkbeat. (He sits on our Reader Advisory Board.) “I have been carrying around quite an alternative narrative about the Common Core, and I felt moved to share it.”

In 17 tweets, Mackert describes how teachers at his school overhauled their assignments to fulfill the standards’ demand that students be able to identify, analyze, and cite evidence from their reading. After students bombed the first round of exams tied to the standards despite those efforts, he writes, teachers made their own tests even more challenging as well. More importantly, he says, they started putting ideas, not isolated reading or math skills, front and center in their lessons.

“In a real way, the Common Core tests were so difficult that they forced us to stop trying to prepare for them so directly,” Mackert writes. “It was terrifying, at first. Then liberating.”

Despite DeVos’s proclamation, the Common Core is still alive and well in many states, even if its name has changed. Mackert said that reality had inspired him, as well.

“I wanted to show that even if the term ‘common core’ is never used again, much of the standards themselves remain, especially in NY where the standards were only lightly revised and rebranded,” he told Chalkbeat.

You can read his whole thread below.