Perforated piano roll and rocket: what they have in common

1. Step 1. Perforated piano roll — is part of — Player piano. Perforated paper with the tune recorded on it.
2. Step 2. Player piano — is made of — Paper. The program is a perforated paper roll.
3. Step 3. Paper — is material for — Rocket. The first rockets were paper tubes filled with gunpowder.

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