[ Ah, he's jumped too far again. Sorry Lakshmi. ]

A clone. Which is just a horrible name for a twin who was created artificially.

[ He pauses a moment, thinking about how best to explain it. ]

Each of us has a pattern in every single one of our cells that tells our body how to grow. That's how identical twins are born - their patterns were copied in the womb, so all factors being equal, you get two identical people.

The same applies here, except you can extract that pattern from any small sample of someone's body. Blood, skin, anything.