Galaxies
What does rotational symmetry mean in Galaxies?
Each connected region must match itself after a half-turn around its single central dot. Mirror symmetry alone is not enough. Every region contains exactly one dot at its rotational centre.
Worked example
If a cell lies two columns right of a dot, its partner lies two columns left at the corresponding opposite position.
What to check on your board
Apply the rule above to your current board, then verify the remaining puzzle constraints. The example explains a local deduction; it is not a solution to every randomly generated board.
Checking your next move
For each proposed cell, locate its half-turn partner around the dot. Check both cells against neighbouring regions before extending the boundary. After the shape is complete, verify connectivity and make sure no second dot has been enclosed.
Using this reference
For Galaxies, read the rule and the worked example together before opening the game. Separate what the rule explicitly requires from what only seems likely on the current board. A useful next move is one you can explain from the visible constraints, not merely a pattern that looks familiar.
If you get stuck, isolate a smaller part of the position and list what is still possible there. After a move, check the affected rows, regions or connections again. The reference explains the documented rules; progress, controls and save behavior belong to the linked game.
Read the developer’s manual ↗ · Open the developer’s browser version ↗
Manual inspected: · Simon Tatham & contributors · MIT