Good idea!
Now instead of using fresh wood for the rings, why not experiment with rubber washers, vinyls, CDs, plastic, salveged leather, (painted) corrugated cardboard, gears or other disc-shaped objects?
And for the bolts/nuts? What about pony/wooden/glass beads, pop bottle lids, pieces of cork, Barbie heads, the erasers on the ends of pencils, dried plant seeds or anything, really!
ARISETOTRASH 