Tape measure and zip: what they have in common

1. Step 1. Tape measure — has part — Spring. A return spring.
2. Step 2. Spring — is part of — Snap fastener. A spring ring.
3. Step 3. Snap fastener — works like — Button. A fastener.
4. Step 4. Button — works like — Zip. An alternative way of fastening.

Open Evothings