The whole transition rule. Click one to switch it off. A green dot marks a recipe you can actually watch fire in his video; the rest are the reconstruction.
On 11 September 2026 Matt Henderson posted a video: a cellular automaton from Minecraft crafting recipes, and then “I added random motion to keep the grid alive — and banned buttons”. The idea is his. There was no code and no write-up, only 40 seconds of video, so the rule below was read off the screen frame by frame; where the video doesn't settle something, this page says so rather than guessing quietly. His original post is here and is worth watching first.
Every cell of the grid holds one item or nothing. Two things happen each tick. Items drift: each cell, with some probability, swaps contents with a neighbour. Then the table works: wherever the items happen to be sitting in the shape of a crafting recipe, that match is outlined, its ingredients are consumed, and the product is put down. The empty squares in a recipe are part of its shape — a chest is eight planks around a hole, and if something drifts into the hole it stops being a chest.
That is all of it. Nothing has a goal, nothing is optimised, and the grid is seeded with only three things — oak logs, oak planks and cobblestone. Everything else on screen, every boat and bowl and pickaxe, is something the grid stumbled into by shuffling.
Read off the video directly: the seed stock (logs, planks, cobblestone in a sparse scatter); the green outline around a match, held for about a second before the craft; a five-plank U becoming a boat, with the boat landing on the ingredient cell nearest the middle of the shape; a stick above a cobblestone becoming a lever; and a closing histogram of item counts sorted downward, led by sticks, cobblestone, cobblestone slabs, planks and oak slabs.
That histogram is the most informative frame in the video, because its ordering is very nearly the ordering of yields — one log makes four planks, two planks make four sticks, three make six slabs. A rule that threw the spare outputs away could not produce it. So this one places them, in the consumed cells first and then the nearest empty ones, and the grid fills up over time the way his does.
Three things the video genuinely does not settle, all of them exposed above as controls rather than decided silently:
Leave it running and the same four things win every time, whatever else you change: oak slabs, oak pressure plates, levers and wooden shovels. They are the cheapest terminal recipes on the board — two or three items each, no exotic shape — so they fire constantly, and nothing in the table ever consumes them again. Within a couple of thousand ticks the grid is mostly those four and a scattering of sticks, and the deep end of the book (chests, furnaces, ladders, signs) almost never fires at all, because eight items in an exact arrangement is a great deal to ask of a random shuffle.
That is not a bug in the reconstruction, it is what a rule with no sinks does, and it is why the recipe book is clickable: switching off the four drains is the fastest way to see how much further the grid can get without them.
A wooden button is one plank in, one button out, and a button is an ingredient in nothing. Leave it in and it is a cancer: every plank that finds itself alone for a moment turns into an inert button, the plank supply collapses, and with it everything downstream — no sticks, so no tools, no ladders, no fences. Unban it in the recipe book and watch. The engine has a test for exactly this, because it is the sharpest thing his two-line follow-up tells you about the rule.
The oak pressure plate is the same trap wearing a different hat — two planks in, one plate out, and plates are an ingredient in nothing either. So is the lever, and so is the wooden shovel. He never mentioned any of them, so they are left in and unbanned here; they are also the three items that end up dominating every run. Switching them off is the single biggest change you can make to how far the grid gets.
The rule runs in a small Rust engine compiled to WebAssembly (engine/ here, 74 KB,
no imports and no bindgen). Each tick it surveys the whole grid for matches — indexed so a cell
only tests the recipes that could start with the item it holds — then fires them in priority
order, with no cell spent twice. The grid is a torus, so a recipe can straddle the seam and the
statistics aren't measuring the edge. Twenty known-answer tests check the shapes against the
game's: a boat is five planks in a U, a chest is eight around a hole, one log is four planks.
No Minecraft assets are used anywhere on this page. Every icon is drawn by
items.js out of a few isometric primitives and a palette per material — it is what
a crafting grid looks like if you draw it yourself. The recipes are the game's, because a
recipe is a fact about the game; the pictures are not facts, so they are ours.
This is a fan page. The idea and the demo are Matt Henderson's (matthen.com, @matthen.com); the code here is ours and none of his video is copied onto this site. If he would rather this did not exist, or wants anything about it changed, that decision is his and we will act on it — see the note on the front page.