Catheter and sickle: what they have in common

1. Step 1. Catheter — is part of — IV drip. A catheter.
2. Step 2. IV drip — has part — Syringe. A needle.
3. Step 3. Syringe — has part — Needle. A hollow needle.
4. Step 4. Needle — evolved from — Stone tool. Bone needles with an eye are part of the Palaeolithic toolkit.
5. Step 5. Stone tool — evolved into — Sickle. The first sickles had flint inserts.

Open Evothings