Celtix

Celtix turns a Celtic knot into a logic puzzle. The grid is filled by ribbons that weave over and under each other, and twenty coloured pips sit along them. Clicking a point where ribbons cross adds a wall there, and the ribbons bounce off it, which splits and rejoins them into new loops.

The goal is a knot in which all the red pips are on one ribbon, all the green ones on another, and so on, with no ribbon left without pips. The game's instructions say real puzzles generally need 12 to 20 walls, and suggest starting from one pip and adding a wall or two to reach another of its colour, then finishing one ribbon before moving on. Your share card shows how many walls you used.

There is one puzzle a day, numbered from the game's start in June 2024, with a countdown to the next and a menu for earlier days. The counter under the board shows how many walls you have placed and how many of the five colours already sit on a ribbon of their own. It keeps your current and best streak, and has colourblind modes that use numbers or shapes instead of colour, a dark mode and a way to move your data to another device. It comes from the same author as 3Doku and Cell Tower.