Pacemaker and archimedes’ screw: what they have in common

1. Step 1. Pacemaker — has part — Lithium-ion battery. A lithium battery (lithium–iodine).
2. Step 2. Lithium-ion battery — is part of — Quadcopter (drone). A lithium-polymer battery.
3. Step 3. Quadcopter (drone) — has part — Propeller. Air propellers.
4. Step 4. Propeller — evolved from — Archimedes’ screw. The first propellers by Smith and Ericsson were a variation on the Archimedes’ screw.

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