I think that is a great way to approach teaching harmony, and allows students to have the maximum amount of creative freedom while still creating something that would sound "nice." How would you address sharps and flats, for example, if a student created an augmented 4th interval. Would you still call that consonant or try to go further with that student? Also, in terms of this exercise with children, do you think it makes more sense for them to copy the rhythm of their first part exactly, so they an see the vertical harmony? Thanks!