cipher is not an encryption explainer. It is a tool for learning to think in fractals about trust, information, and the systems people build to make communication reliable. Cryptography is the subject. Fractal thinking is the skill.
Each concept is a physical object you can cut into. A lock, a mailbox, a wax seal, a signet ring, a notary's register. Every object is drawn in cross-section, the way a product designer would draw a mechanism to show how it works inside. Zoom is not a scroll. Zoom is a cut closer.
Every object raises the problem the next object solves. The spiral is the point. You do not leave cipher knowing how encryption works. You leave cipher expecting every complex system to have a spiral like this one.
For the writer, the designer, the curious, the recently confused.
Six objects on one desk. Five are the concepts. The first is the one you have already seen ten thousand times without looking at it.