Explain it from zero

Learn any topic with an analogy, the key ideas and a quick self-test.

Explain {{TOPIC}} to me. I know {{WHAT I ALREADY KNOW}} but nothing about this topic.

1. One-sentence definition with no jargon.
2. An everyday analogy, and where the analogy breaks.
3. The 3-5 key ideas, in the order I should learn them.
4. A concrete worked example.
5. The most common misconception and why it is wrong.
6. 3 questions to test my understanding (answers at the end, hidden under "Answers").

If something is debated among experts, say so.