Drill steel rod with bit and plumbing: what they have in common

1. Step 1. Drill steel rod with bit — is part of — Rock drill. A steel rod with a bit.
2. Step 2. Rock drill — is used in — Tunnel. Driving the Mont Cenis tunnel.
3. Step 3. Tunnel — is used in — Metro. Tunnels.
4. Step 4. Metro — is made of — Brick. The vaults of the first tunnels are brick.
5. Step 5. Brick — is material for — Water tower. Water towers are brick.
6. Step 6. Water tower — is part of — Plumbing. Maintaining pressure.

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