Reins and centrifugal pump: what they have in common
- Step 1. Reins — is part of — Bit and bridle. Control.
- Step 2. Bit and bridle — is made of — Leather. A bridle is leather straps.
- Step 3. Leather — is material for — Fire pump. The hoses were sewn from leather.
- Step 4. Fire pump — evolved into — Fire truck. A pump on a motor-vehicle chassis.
- Step 5. Fire truck — has part — Centrifugal pump. A fire pump.