Recumbent bicycle and hollerith tabulator: what they have in common
- Step 1. Recumbent bicycle — has part — Roller chain. The drive is by chain.
- Step 2. Roller chain — is part of — Electric bicycle. The chain drive from the pedals remains.
- Step 3. Electric bicycle — has part — Hub motor. A hub motor or a mid-drive motor.
- Step 4. Hub motor — uses — Electromagnetism. A hub motor is an electric motor.
- Step 5. Electromagnetism — is used in — Hollerith tabulator. The counters click with electromagnets.