Shield and rocket: what they have in common

1. Step 1. Shield — is made of — Leather. Leather on a wooden base.
2. Step 2. Leather — is material for — Fire pump. The hoses were sewn from leather.
3. Step 3. Fire pump — evolved into — Fire truck. A pump on a motor-vehicle chassis.
4. Step 4. Fire truck — has part — Centrifugal pump. A fire pump.
5. Step 5. Centrifugal pump — is part of — Liquid-propellant rocket engine. Turbopumps deliver the propellant.
6. Step 6. Liquid-propellant rocket engine — evolved from — Rocket. Goddard switched to liquid fuel.

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