Demonstrate hard-to-understand rhythms by placing marbles (or similar) in notches relating the location of individual notes to the beat. Instead of marbles, you can also use wooden beads, candy (ie Skittles, M&Ms, or gumballs). Correlates to lessons in the Creative Chords keyboard improvisation series.
Note: Handmade from repurposed wood so colour variations and imperfections are normal. Marbles not included.