Each concept here is mapped to its prerequisites — the ideas you'd need first to understand it — all the way down to four foundations: Space, Time, Energy, Pattern. Click any prerequisite to drill down, or scroll for the chain graph.
A lesson emerges from the act of instruction, where a period of teaching or learning on a specific topic or skill is structured around defined objectives and content.
External reference — all senses of the word “lesson” on Wiktionary. This atlas concept maps to only the slice of meaning relevant to the prerequisite graph.