Magic lantern and barrel: what they have in common

1. Step 1. Magic lantern — uses — Oil lamp. The light source is an oil lamp.
2. Step 2. Oil lamp — is made of — Clay. Later — clay ones.
3. Step 3. Clay — is material for — Qanat. Weak sections of a qanat were reinforced with clay rings.
4. Step 4. Qanat — works like — Aqueduct. An underground channel instead of an overground one.
5. Step 5. Aqueduct — has part — Arch. Roman aqueducts rested on arcades.
6. Step 6. Arch — works like — Barrel. Staves squeezed by hoops hold their shape by the same compression as the stones of an arch.

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