In my high school art class, I had a project with which you can pick the medium, unlike the others. Since I enjoy creating things much better than failing at trying to shade and put in value, I eventually settled on a making a mobile. After that I decided to give it a steam punk vibe, with the gears, copper pipe stand, etc. I'm pretty happy with the outcome, although I don't have anywhere to put it now....
Clutch plates holders, and maybe the torque converter ring is where the big ring is from. Its been over 30 years since i did transmissssioooon work, but the parts stick with you.