One of the rituals when I took my Kodály levels at PSU was to for all the levels to warm-up together in the morning.  One morning Jill Trinka taught us this round:

I LOVE the round but it's pretty tricky for my kids to sing: the jump from do to high mi is really difficult for them.  So, I took the mi', re' and do' down an octave (as notated below) and use it with my 4th graders to reinforce fa.