Piano and zip: what they have in common

1. Step 1. Piano — is made of — Felt. The hammers are covered with felt.
2. Step 2. Felt — is made of — Wool. Matted wool.
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.

Open Evothings