Knife and tunnelling shield: what they have in common

1. Step 1. Knife — has part — Handle. A handle.
2. Step 2. Handle — is part of — Chisel. A wooden or plastic handle.
3. Step 3. Chisel — is used in — Tunnel. Hezekiah’s Tunnel was cut by hand with chisels.
4. Step 4. Tunnel — uses — Tunnelling shield. Shield tunnelling.

Open Evothings