Interactive explainers
Moving Parts
Big ideas in mathematics, computer science and physics, taken apart so you can watch them work.
Each explainer is a story told through live demos. The figures run the real algorithms and train real models right in your browser, so you can play them, pause them, step through them one move at a time, and change the inputs to see what happens.
The explainers
- Algorithms · 2022–2025 Beyond Dijkstra Dijkstra's 1956 shortest-path algorithm has two built-in limits: it fails on negative costs, and it can never beat sorting. Between 2022 and 2025, both fell. Watch the new algorithms run, step by step. Starts in the deep end 4 chapters · Playground
- Machine learning · 1988–2026 From Black Box to Rulebook How do you get readable IF–THEN rules out of a neural network? Follow the answers from 1988 to today, with demos that train real models and pull out their rules in your browser. Starts in the deep end 6 chapters · The Lab
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Astrophysics · a course The Clockwork Sky An introduction to astrophysics that starts from scratch: why the Moon has phases, how we weigh the Sun, and on from there to how stars are born, shine and die. Starts from the basics Coming soon