Front-mounted pedal crank and telephone: what they have in common

1. Step 1. Front-mounted pedal crank — is part of — Recumbent bicycle. Pedals at the front.
2. Step 2. Recumbent bicycle — has part — Roller chain. The drive is by chain.
3. Step 3. Roller chain — is used in — Derailleur. It moves the chain across.
4. Step 4. Derailleur — has part — Spring. A tension spring.
5. Step 5. Spring — is part of — Rotary dial. A return spring.
6. Step 6. Rotary dial — is part of — Telephone. A dial.

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