Recumbent bicycle and rock drill: what they have in common

1. Step 1. Recumbent bicycle — has part — Roller chain. The drive is by chain.
2. Step 2. Roller chain — is part of — Roller coaster. A chain lift.
3. Step 3. Roller coaster — uses — Railway track. Rails.
4. Step 4. Railway track — is used in — Metro. It runs on rails.
5. Step 5. Metro — uses — Tunnel. Tunnels.
6. Step 6. Tunnel — uses — Rock drill. Driving the Mont Cenis tunnel.

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