Whistle edge and syringe: what they have in common

1. Step 1. Whistle edge — is part of — Whistle. A sharp edge that splits the air stream.
2. Step 2. Whistle — is made of — Bone. Ancient whistles were carved from bone.
3. Step 3. Bone — is material for — Needle. The first needles with an eye were carved from bone.
4. Step 4. Needle — is part of — Syringe. A hollow needle.

Open Evothings