You're welcome. It's useful and enjoyable for me to see how people think through their teaching.

Should you want to find out more you can search "productive struggle nctm/math/teaching." The concept came to me via the math education community but I would actually recommend starting out with the work of Robert and Elizabeth Bjork [0,1].

The Bjorks have researched the same concept extensively. Their term for it is "desirable difficulties."

Their work made the leap from academia to popular culture via David Epstein's book, Range.

[0] https://researchschool.org.uk/durrington/news/bjorks-desirab...

[1] https://bjorklab.psych.ucla.edu/robert-a-bjork-publications/