Saddle tree frame and lead–acid battery: what they have in common
- Step 1. Saddle tree frame — is part of — Saddle. The saddle tree.
- Step 2. Saddle — is made of — Leather. A saddle is made of leather.
- Step 3. Leather — is material for — Submarine. It was covered with leather.
- Step 4. Submarine — has part — Lead–acid battery. Underwater, electric motors run on batteries.