Bulldozer and oil lamp: what they have in common

1. Step 1. Bulldozer — has part — Hydraulic cylinder. The blade is raised by hydraulics.
2. Step 2. Hydraulic cylinder — is part of — Tunnel boring machine. Hydraulic cylinders push the machine forward.
3. Step 3. Tunnel boring machine — is made of — Cemented carbide. The cutters are cemented carbide.
4. Step 4. Cemented carbide — is made of — Tungsten. Tungsten carbide.
5. Step 5. Tungsten — is material for — Incandescent light bulb. A tungsten filament (since 1904–1910).
6. Step 6. Incandescent light bulb — evolved from — Oil lamp. The electric lamp replaced oil and gas lamps.

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