It's a story about students with some internal desire to be good at pottery, not just to get good grades. The grading system forces them over the hurdle of hesitation, to produce quantity without being paralyzed by anxieties over not being good enough, and then their own desire to improve nonetheless uses that imposed practice productively.
It would make more sense if they were just graded on number of pieces, considering it's a story not something that actually happened, they should just correct it.
