School bell and internal combustion engine: what they have in common

1. Step 1. School bell — is a kind of — Electric bell. An electric bell.
2. Step 2. Electric bell — has part — Light switch. A button.
3. Step 3. Light switch — is made of — Porcelain. The body is porcelain.
4. Step 4. Porcelain — is material for — Spark plug. The insulator is ceramic.
5. Step 5. Spark plug — is part of — Internal combustion engine. A petrol engine ignites the mixture with a spark plug.

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