Screwdriver shaft and railway semaphore: what they have in common

1. Step 1. Screwdriver shaft — is part of — Screwdriver. A steel rod.
2. Step 2. Screwdriver — uses — Torque. The handle creates torque.
3. Step 3. Torque — is used in — Lever. A lever is a moment of force around a fulcrum.
4. Step 4. Lever — is used in — Railway semaphore. The semaphore is set by a lever.

Open Evothings