Looking for a blog article on the UI/UX design of an interactive coding interface like Khan Academy's
I found it !! Boy, I'm so glad. Had a bolt of insight in how I should use Google's advanced search features, and I found it.
Here is the article:
http://worrydream.com/LearnableProgramming/
An article by Bret Victor, from 2012. A great read, for those curious.