Smallpox vaccine and solar panel: what they have in common

1. Step 1. Smallpox vaccine — is a kind of — Vaccine. The first vaccine.
2. Step 2. Vaccine — uses — Syringe. Injections.
3. Step 3. Syringe — is made of — Silver. Early needles were silver.
4. Step 4. Silver — is material for — Wall mirror. Silvering.
5. Step 5. Wall mirror — has part — Window glass. Sheet glass.
6. Step 6. Window glass — is part of — Solar panel. Tempered cover glass.

Open Evothings