The catch: every galaxy must look exactly the same after being turned halfway round its dot. That 180° symmetry is the whole puzzle.
Galaxies rules in 30 seconds
- 1Divide the whole board into regions called galaxies.
- 2Each galaxy contains exactly one dot.
- 3Each galaxy is symmetric under a 180° turn around its dot.
- 4Each galaxy is one connected piece.
See it on a board
Think in pairs
Pick any cell in a galaxy and spin it half a turn around the dot. Where it lands must be in the same galaxy. So cells always join a galaxy in pairs, and every time you grow one side, the mirror side grows too.
Where dots can sit
- In a cell: that cell is the galaxy's centre.
- On an edge: the two cells either side belong together.
- On a corner: all four cells around it belong together.
- A border can never pass through a dot.
How to start a Galaxies puzzle
- Mark every edge that passes through a dot as open. Those cells always stay together.
- Draw borders between neighbouring cells that belong to different dots' cores.
- Find cells only one dot can reach, then add their mirror cells straight away.
- Finish the galaxies squeezed against the board edge first; the edge cuts off half their options.
Worked example
- 1A dot sits one cell away from the right edge of the board.
- 2A cell two steps to its left would mirror to a spot off the board on the right.
- 3So that cell can't belong to this galaxy. The galaxy can extend left at most one cell.
Galaxies tips and strategies
Mark the certain cores
Cells touching a dot on an edge or corner always belong together.
Use the board edge
If a cell's mirror would fall off the board, it isn't part of that galaxy.
Find cells with one option
A cell only one dot can reach belongs to that dot's galaxy.
Borders are shared
Finishing one galaxy draws part of its neighbour's outline too.
Common mistakes to avoid
- Drawing a border through a dot.
- Growing one side of a galaxy without its mirror.
- Sealing off an area that contains no dot.
Play Galaxies in 10+ Number Puzzles
- Tap the edge between two cells to draw or remove a border; long-press to place an X, a note that the edge stays open.
- Switch on X Mark to swap the two.
- Auto Notes adds X marks on every edge through a dot.
- Some impossible borders are caught at once and cost a life, like one that seals off an area with no dot.
- Boards grow from 5×5 on Easy to 9×9 on Genius.
- Five difficulty levels, each a ladder of stages from Easy to Genius.
- Go online for free: ranked 1v1 duels, rooms where you race, co-op or play in teams, and tournaments.
- 27 more puzzle types in the same app, and online play never costs coins.
Galaxies FAQ
What is a Spiral Galaxies puzzle?
The same puzzle as Galaxies: split the grid into regions that each hold one dot and are symmetric under a half turn around it.
Does every galaxy need a dot?
Yes. Every region contains exactly one, and the dot is its centre of symmetry.
Can a galaxy be any shape?
Any shape at all, as long as it's connected and looks the same after a 180° turn around its dot.
