Billiard cue and zip: what they have in common

1. Step 1. Billiard cue — is part of — Billiards. A stick for striking.
2. Step 2. Billiards — is made of — Wool. The baize.
3. Step 3. Wool — is material for — Trousers. The oldest trousers (Yanghai) were sewn from wool.
4. Step 4. Trousers — has part — Zip. A fastener.

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