Daily puzzle game
Color every node so that no two joined by a line match. There is always a solution, though it is rarely obvious. A new board comes out every morning, the same one for everyone.
Free to play · Pro is optional
The rule
Two nodes joined by a line can’t share a color. Four colors are always enough: every board is planar, and a planar map never needs a fifth. That’s a proven theorem.
Every color also has its own shape, so you can play without telling colors apart.
Ways to play
A Standard board every day, and a Hard one too with Pro. Everyone gets the same boards, and the leaderboard closes at midnight UTC. If you miss a day, a freeze keeps your streak: you get one for every seven days in a row and can hold up to two on each board.
As many boards as you like, with no streak and no leaderboard, only your own best times. Every tier uses the same four colors. The board grows instead: more nodes, and more of them left empty.
One open duel with each friend at a time: the same board for both of you and twenty-four hours to play it. Wins, losses and draws go into a history you can both see.
With Pro you can play past boards any time. They don’t change your streak. The archive is there to catch up on days you missed.
Cantle ProA second board every day on Hard, with its own streak and its own leaderboard. The full archive from day one, so you can play any day you missed. The two largest tiers, Proof and Axiom, in practice and in duels. Pro is a monthly or yearly subscription. Board themes, symbol sets and wallpapers can also be bought one by one. The game itself is free and has no ads.
Getting faster
With no color picked, each tap on a node cycles through all four. Pick a color on the palette first and one tap is enough. A long press clears a node.
When two joined empty nodes have the same two colors left, each of them takes one. So a node joined to both can use neither color, and that is often enough to settle it.
If a node’s neighbors already show three different colors, it gets the fourth. Place it and look again: one such move usually decides the next, and on most boards the chain goes all the way to the end.
A ring with an odd number of nodes can’t be colored with two colors: somewhere the pattern breaks and a third color is needed. Counting first is quicker than undoing later.
When two joined nodes match, the red ring appears on the one you placed last. It shows which move to take back, though the real mistake is often the move before it.
The details
What’s not here
There are no ads and no third-party analytics in the app, so there’s nothing to switch off. No email or password either: your phone gets an anonymous ID and a friend code, and that’s the whole account. Crash reports go only to my own server in Frankfurt.
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 it has.
I read about it a few years ago and couldn’t stop thinking about it. One rule with no instructions, and a board that always has a solution but rarely shows it at first glance. It wanted to be a game.
So I made it myself, in the evenings and on weekends, server included.
And I kept it small on purpose. There are no ads, because I didn’t want to write the code that shows them, and no account, because nobody should need an email address to play a puzzle. There’s no analytics either: I don’t want to watch you play.
Play it. If something breaks, something’s missing, or you 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 and Google Play
Free to play · No ads