piano notes and letters

I am pretty lucky to have a piano in the classroom again - it is an amazing instrument for the children to explore independently.  J explored with her whole body, rocking to the tune that she made, and then creating her own meaning by labeling different notes with letters corresponding to her friends' names.  This abstract labeling system for the notes is fascinating to me because it is how the notes are labeled according to musicians.  I have to ask myself, what other ways might the children choose to represent the notes on the piano?