Galaxies

Overview

Galaxies asks you to partition a grid around a collection of small centre dots. Each resulting region must contain exactly one dot and look unchanged when rotated halfway around that dot. A centre may sit inside a square, on an edge, or at a grid intersection, so the smallest possible region varies from dot to dot. Regions must be connected and together cover every square. This is a spatial deduction puzzle rather than a drawing challenge: every boundary changes which symmetric partners remain possible. Long narrow regions can be valid if their opposite halves match. The local Galaxies engine generates fresh boards and supplies the familiar New, Restart and Undo controls for experimenting with different partitions.

How to Play

Click grid edges to add or remove region boundaries. Place each border with its rotational counterpart in mind: a wall one square to the right of a centre implies the matching wall on its left. Secondary-drag from a centre dot into a cell to mark that cell as belonging to the centre's region. For accurate phone input, make short taps on individual edges and use Undo when a neighbouring edge catches the tap. Continue dividing the grid until all regions surround one centre, remain connected, and satisfy half-turn symmetry.

Tips & Strategy

Start beside the outer border, where one side of a potential galaxy cannot extend beyond the grid. Reflect that limit through its centre to constrain the opposite side. Centres on intersections initially need the four surrounding cells, while an edge centre needs the two cells sharing that edge. Look for a square that only one centre can reach symmetrically; assigning it forces its opposite partner immediately. Avoid closing a region merely because its outline looks balanced. Check that it contains its own centre, no second centre, and no disconnected pocket of matching-looking squares.

About this version

Galaxies uses the locally compiled galaxies engine from Simon Tatham’s Portable Puzzle Collection. The original authors retain credit under the MIT license. SonoTap provides the browser adaptation and this guide.