White starts. Players alternate placing stones on empty cells.
After a placement, every newly-fully-filled square (2×2 and larger) that is
horizontally or vertically mirror-symmetric flips all its stones
to the placing player's color.
Diagonal symmetry does not count. Multiple squares may flip per move.
The board fills up. Most stones of your color wins.
Symmetry - The Board Game is designed by Thomas de Haan