I still like my math analogy for what 'progressive' really means vs the WT version.
I studied Algebra in 9th grade. In 10th grade I studied Geometry. It was different from what I studied in 9th grade but what I studied in 9th grade was still true and useful
In 11th grade I studied Trigonometry. Interesting stuff. Different from 9th and 10th grade. What I learned in 9th and 10th grade was still true and useful.
12th grade. Calculus. Now we are getting somewhere. But still, what I learned in 9th, 10th, and 11th grade was still true and useful.
And on and on it goes. 3 more semesters of calc in college and then onto differential equations (almost got convinced to change major to math).