What do they mean? Do they represent anything? Wouldn't there be more of a point to them if you tested into a level?
I don't know what they mean, either, other than probably arbitrary stages--could have been made longer, or could have been shorter. I'd like to know, too, if it is more than that. You DO test into a level. If you don't pass your quizzes--if the owl hoots--you won't progress to another stage, I don't think.