Daily puzzle game
Color every node so that no two joined by a line ever match. It is never impossible, and it is rarely obvious. A new board arrives each morning, the same one for everyone.
Out now on the App Store · Google Play in October
Free to play · Pro is optional
The rule
Two nodes joined by a line cannot share a color. Four are always enough, because every board is planar, and a planar map has never needed a fifth. That is a theorem, not a promise we are making.
Every color carries a shape, so the board stays solvable without relying on color at all.
Ways to play
A Standard board every day, plus a Hard one with Pro — the same boards for everyone, and a leaderboard that closes at midnight UTC. Miss a day and a freeze can cover it: you earn one for every seven days in a row, up to two, on each board.
Unlimited boards, with no streak and no leaderboard — just your own best times. Every tier is still four colors. What grows is the board: more nodes, and more of them left for you to fill.
One open duel with each friend, the same puzzle for both of you, twenty-four hours to answer. Win, lose or draw goes into a history you can both read.
With Pro, past boards are playable whenever. Solving one leaves your streak exactly as it was: the archive is for catching up, and it cannot repair a run.
Cantle ProA second board every day on Hard, with its own streak and its own leaderboard. The full archive, back to day one, so any day you skipped can still be played. And the two largest tiers, Proof and Axiom, in practice and in duels. Pro is a subscription, monthly or yearly. Board themes, symbol sets and wallpapers can also be bought one by one. The game itself is free, and there is no advertising anywhere.
Getting faster
Tapping a node without choosing first cycles through all four. Select from the palette and each tap is one move instead of up to four. Long-press clears a node outright.
When two joined empty nodes have the same two colors left, those two will split between them, one each. So any node touching both can take neither — which is often enough to settle it outright.
A node whose neighbors already show three different colors has exactly one color left. There is nothing to think about. Place it and look again, because that one placement usually decides the next, and on most boards the chain runs all the way to the end.
A ring with an odd number of nodes never fits two colors, however you arrange them: somewhere the alternation has to break, and a third color goes in. Counting first is cheaper than undoing later.
When two joined nodes match, the red ring is on the one you just placed. It tells you which decision to take back. Usually that is the one before it, not the one you are looking at.
The details
What we left out
No advertising and no third-party analytics. Neither is built into the app, so there is nothing to opt out of. You give us no email address and no password: your device gets an anonymous ID and a friend code, and that is the whole account. Crash reports go to our own server in Frankfurt, never to a tracking vendor.
A note from me
There is a theorem that went unproved for 124 years: four colors are enough for any map you can draw on a flat page. However many countries, however many borders, four will always do.
I read about it a few years ago and couldn’t stop turning it over. One rule. No instructions. A board that is never impossible and rarely obvious. It was asking to be a game.
So I made one. Evenings and weekends, by myself. Every board, every color, every line of the server it talks to.
And I kept it small on purpose. No advertising, because I didn’t want to write the part that shows it. No account, because handing over an email address to play a puzzle is an indignity. No analytics, because I’d rather not watch you.
Play it. If something is broken, or missing, or you just think it should work differently, write to me. [email protected] for anything about the game, [email protected] for anything about your data.
Yurii
Today’s board
Out now on the App Store · Google Play in October
Free to play · No ads · No sign-up