Supermarket and bellows: what they have in common

1. Step 1. Supermarket — uses — Cash register. Tills.
2. Step 2. Cash register — has part — Keyboard. Sums were entered with keys.
3. Step 3. Keyboard — is part of — Pipe organ. Manuals were the first keyboards.
4. Step 4. Pipe organ — has part — Bellows. Bellows supply the air.

Open Evothings