Hairpin and telephone: what they have in common

1. Step 1. Hairpin — uses — Elasticity. Elasticity.
2. Step 2. Elasticity — is used in — Spring. A spring works through the elasticity of its material.
3. Step 3. Spring — is part of — Rotary dial. A return spring.
4. Step 4. Rotary dial — is part of — Telephone. A dial.

Open Evothings