Leaf spring and gas lamp: what they have in common

1. Step 1. Leaf spring — is part of — Truck. Leaf-spring suspension.
2. Step 2. Truck — evolved into — Ambulance. A special-purpose vehicle.
3. Step 3. Ambulance — has part — Ventilator. Medical equipment.
4. Step 4. Ventilator — has part — Valve. Valves.
5. Step 5. Valve — is part of — Gas lamp. A gas supply valve.

Open Evothings