After learning to categorize the instruments, I show the students how we can use a shape to represent each group. I pass out the instruments and they have to group themselves according to their instrument and shape.
Next, I show the students these Aleatoric Maps, created by my friend Charlotte, and they play their instrument as I trace the line. You can also trace from each end point as well as point slower or faster. We do several of these together and then I have a few students come to the board to make one collaboratively.