How the ideas connect

The Skills ladder shows every connected chapter on one map, with one line per subject and the foundations at the bottom. Chapters further right build on more earlier ideas.

Search by topic, idea or lesson code, pause on a chapter to preview what it needs and what it opens up, then open its full map to see why each connection matters.

Links open each chapter with its existing access settings. Prefer a plain list? Browse all explainers instead.