Smart speaker and hollerith tabulator: what they have in common

1. Step 1. Smart speaker — has part — Loudspeaker. A loudspeaker.
2. Step 2. Loudspeaker — uses — Electromagnetism. A coil carrying current in the field of a permanent magnet moves the diaphragm.
3. Step 3. Electromagnetism — is used in — Hollerith tabulator. The counters click with electromagnets.

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