Bifacially knapped stone surface and electrical telegraph: what they have in common

1. Step 1. Bifacially knapped stone surface — is part of — Hand axe. Flaking on both sides gives a symmetrical edge.
2. Step 2. Hand axe — evolved into — Axe. A hand axe mounted on a handle.
3. Step 3. Axe — uses — Lever. The haft lengthens the arm of the blow.
4. Step 4. Lever — is used in — Optical telegraph. The arms were moved by a system of levers and rods.
5. Step 5. Optical telegraph — evolved into — Electrical telegraph. The electrical telegraph replaced semaphore lines.

Open Evothings