Buckle and centrifugal pump: what they have in common

1. Step 1. Buckle — is part of — Watch strap. A buckle.
2. Step 2. Watch strap — is made of — Leather. Leather.
3. Step 3. Leather — is material for — Fire pump. The hoses were sewn from leather.
4. Step 4. Fire pump — evolved into — Fire truck. A pump on a motor-vehicle chassis.
5. Step 5. Fire truck — has part — Centrifugal pump. A fire pump.

Open Evothings