Axe handle and boiler: what they have in common

1. Step 1. Axe handle — is part of — Axe. A handle.
2. Step 2. Axe — evolved from — Hand axe. A hand axe mounted on a handle.
3. Step 3. Hand axe — is a kind of — Stone tool. A hand axe is a kind of stone tool.
4. Step 4. Stone tool — evolved into — Hammer. The first hammer was a stone in the hand.
5. Step 5. Hammer — evolved into — Steam hammer. A steam hammer is a hammer lifted by steam, used to forge huge parts.
6. Step 6. Steam hammer — has part — Boiler. A boiler supplies the steam.

Open Evothings