Looking at the css for the page, I can see what all the intervals are, or should be based on class names. Let me just compile these…
Lessons
0 lessons
class lessons-and-reviews__lessons-button–0
1-24 lessons
lessons-and-reviews__lessons-button–1
25-49 lessons
lessons-and-reviews__lessons-button–25
50-99 lessons
lessons-and-reviews__lessons-button–50
100-249 lessons
lessons-and-reviews__lessons-button–100
250-499 lessons
lessons-and-reviews__lessons-button–250
500+ lessons
lessons-and-reviews__lessons-button–500
Reviews
0 reviews
lessons-and-reviews__reviews-button–0
1-49 reviews
lessons-and-reviews__reviews-button–1
50-100 reviews
lessons-and-reviews__reviews-button–50
100-249 reviews
lessons-and-reviews__reviews-button–100
250-499 reviews
lessons-and-reviews__reviews-button–250
500-999 reviews
lessons-and-reviews__reviews-button–500
1000+ reviews
lessons-and-reviews__reviews-button–1000
That took longer than I thought…
I’m surprised there’s illustrations for 250+ and 500+ lessons, since it’s impossible to get these without a reorder script to skip vocab lessons or something.