I taped out an xylophone shape for each of my boys on some cardstock. I then taped it to the table so it wouldn't move.
We used tempera paint for this tape resist art, but you are welcome to use any medium your child enjoys. We have used primarily dot markers in the past for these types of art projects, but the boys were eager to use their paint brushes for this craft! J preferred to paint "really fast!!" while K favored a more careful, gentle technique.
Regardless, the end result was fantastic! Here's J's xylophone:
And here's K's finished xylophone: