That's beautiful! It must be 20 years that I've been subconsciously bothered by that puzzle, because I couldn't understand what “more fun” was supposed to mean in that context. With ‘where’ in place of ‘while’ and “a better effect on the teacher” in place of “more fun”, it sudddenly makes sense.

Also, the linked article links to “List of linguistic example sentences” (http://en.wikipedia.org/wiki/List_of_linguistic_example_sent...), which introduced me to a beautiful Mitch Hedberg quote:

> I haven't slept for ten days, because that would be too long.

and helped me remember a word that has been eluding me for some time: http://en.wikipedia.org/wiki/List_of_linguistic_example_sent.... Thanks!