Absorbent sample pad and screw press: what they have in common

1. Step 1. Absorbent sample pad — is part of — Pregnancy test. It receives the sample.
2. Step 2. Pregnancy test — uses — Capillary action. Capillary flow of the liquid.
3. Step 3. Capillary action — is used in — Fountain pen. Ink flows through the nib’s capillaries.
4. Step 4. Fountain pen — uses — Ink. Ink.
5. Step 5. Ink — is used in — Gutenberg printing press. An impression needs ink; Gutenberg used an oil-based one.
6. Step 6. Gutenberg printing press — has part — Screw press. Gutenberg adapted the screw press known from pressing grapes.

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