How to Write a Quine: A Guide to Self-Replicating Code
I explain the mechanics of a quine, a program that prints its own source code without introspection, using an allegory of a machine that builds copies of itself from a plan. I then walk through the step-by-step process of constructing a simple quine in Python, demonstrating how to insert a plan into a program to achieve self-replication.
This whole story about the machine is not an independent puzzle; it doesn't even have to make perfect sense, it only serves to help you understand better why the quine I'll write in a moment is built the way it is and how it works.