Play Spiral Galaxies puzzle (Galaxies) online Works — plays right here, unlimited puzzles
Guide updated October 2026 · Runs via WebAssembly (native port)
Spiral Galaxies is a region-drawing puzzle: the grid is dotted with centres, and you draw walls so that each region contains one dot and looks the same when turned upside down around it. The Japanese original is Nikoli's Tentai Show. The puzzle is ready below; click a grid line to draw a wall.
Controls — what does what
| Action | Keyboard | Mouse / touch |
|---|---|---|
| Draw or remove a wall | Arrow keys to a line, then Enter | Left-click the line |
| Drop a reminder arrow pointing at a dot | Enter on a dot, move, Enter again | Right-drag from the dot into a square |
| Move or delete a reminder arrow | Enter to pick up; drop on a dot to remove | Right-drag it; drop off the grid to delete |
| Undo / redo | U / R (or Ctrl+Z / Ctrl+R) | Game menu buttons |
FREE This is the complete game, free. Open source under the MIT licence: the complete puzzle, with a new grid every time.
Galaxies is from Simon Tatham's Portable Puzzle Collection, © Simon Tatham and contributors, used under the MIT licence. Built from source by scripts/build-puzzles.mjs.
How to play
- Divide the whole grid into regions along the grid lines.
- Each region contains exactly one dot, which may sit in a square, on an edge or at a corner.
- Each region has 180° rotational symmetry about its dot: turned half a circle around the dot, it lands on itself.
- Walls go only between squares in different regions.
A correct, closed region is highlighted automatically, so the aim is to get the whole grid highlighted.
Sizes and difficulty
Presets are 7×7, 10×10 and 15×15, each at Normal or Unreasonable. Unreasonable may need backtracking.
Solving tips
Any square touching a dot belongs to that dot's region, and so does its mirror image through the dot. Draw walls between neighbouring dots: two dots cannot share a region. Whenever you assign a square to a dot, immediately mark the symmetric square too. A square that only one dot can reach symmetrically must belong to it; the reminder arrows are handy for recording that.
Where this puzzle comes from
Galaxies is part of Simon Tatham's Portable Puzzle Collection, a set of about forty logic puzzles written by Simon Tatham and contributors and released under the MIT licence. Every grid is generated on the spot, so the supply never runs out, and for the grid-logic puzzles the generator makes sure each has exactly one solution, reachable by reasoning rather than guessing. The version here is the collection's own code compiled to WebAssembly; the Game menu can save a puzzle to a file and load it again, and the Type menu changes the size and difficulty.
Frequently asked questions
Can a dot sit on a line?
Yes. Dots can be in the middle of a square, on an edge between two squares, or at a corner where four squares meet; the region is symmetric around that point.
How do I know when a region is right?
It gets shaded once it is closed, holds exactly one dot, is symmetric about it and has no stray walls inside.
Is Galaxies free to play here?
Yes, with no limit on the number of puzzles. Galaxies is open-source software under the MIT licence, and every grid is generated fresh when you press New game.
Does it work on a phone or tablet?
Yes. A tap works as a click and the puzzle resizes to fit the screen. Puzzles whose controls use the right mouse button are easier with a mouse.
More you can play in your browser
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Want a game like this on your own site?
Spiral Galaxies puzzle (Galaxies) isn't ours to give away — we host it, we didn't write it. But eleven of the games here we did write from scratch, and those are free for anyone to put on their own page: one line of HTML, no account, no permission, no attribution beyond a credit line.