Have the y-axis represent effort required to advance, and x-axis level of mastery achieved. F.ex “effort“ could be quantified as topics in a book to cover bef

Have the y-axis represent effort required to advance, and x-axis level of mastery achieved. F.ex “effort“ could be quantified as topics in a book to cover before being ready for the next chapter, and “mastery” as simply number of chapters read.