A world of borders.
Only four colours.

Give every region its place. Keep neighbours apart.

YOUR CARTOGRAPHER'S KIT

Make room for colour.

Choose a region and a colour. Then paint more regions with a click.

A few border agreements

Colour every region with one of four colours.
Regions sharing an edge must have different colours. Touching at a corner is fine.
Colours marked with a ◆ are fixed clues. They stay where they are.

Numbers identify regions; they are not clues. Symbols distinguish colours without relying on colour alone.

1–4 paint · Arrows select · Delete erase
N notes · U undo · Escape deselect paint

About this atlas

Map, from Simon Tatham's Portable Puzzle Collection. Fifteen uniquely solvable maps generated and solved by the original C engine; a new browser interface. Pencil notes are optional.

Hints reveal one region from the solution and mark that atlas assisted. Your progress stays on this device.

Pinned GitHub source · MIT license

A world of borders.Only four colours.

A world of borders.
Only four colours.