The same 21 points, solved four different ways. Click anywhere on it to add a point of your own and watch every method disagree about what you just did.
42 concepts · every number editable · zero static diagrams
Every point joins its nearest centre; every centre moves to the average of its points.
Each one is a page where the surprise is the point — the algorithm does something you did not expect, and the reason is visible on screen.
Each track runs in order and every page links to the next, so the whole thing can be read straight through.
All 42 concepts. The sidebar carries the same list on every page, and ⌘K searches it from anywhere.