Revolving door and jacquard loom: what they have in common

1. Step 1. Revolving door — has part — Ball bearing. The axis.
2. Step 2. Ball bearing — is part of — Ballpoint pen. A ball in a socket — essentially a ball bearing.
3. Step 3. Ballpoint pen — uses — Ink. Thick oil-based ink.
4. Step 4. Ink — is used in — Gutenberg printing press. An impression needs ink; Gutenberg used an oil-based one.
5. Step 5. Gutenberg printing press — works like — Jacquard loom. An analogy, not proven influence: both set type and a chain of punched cards are a replaceable pattern that a machine reproduces over and over.

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