DVD and submarine: what they have in common

1. Step 1. DVD — is a kind of — Optical disc (CD/DVD). An optical disc.
2. Step 2. Optical disc (CD/DVD) — uses — Reflection of light. Reflection from the pits.
3. Step 3. Reflection of light — is used in — Periscope. Reflection.
4. Step 4. Periscope — is part of — Submarine. A periscope.

Open Evothings