A grid-based logic puzzle
Color each cell black or white… and give your brain a workout.
Get Some Puzzles
Symmetry (⟍, |, ⟋, ― et 🞋)
Whenever a cell contains one of those symbols, the group it belongs to must respect a symmetry along that axis.
The central symmetry (🞋) is identical to a rotation by half a turn.
This black cell with a "⟍" tells us that the group must be symetrical along a diagonal axis.
It already has another black cell below it so by symmetry, we must have a black cell on its right.
Now, still looking at this black group, we see that its on the side of the grid so it cannot extend on its left.
So, based on the symmetry, it cannot extend on its top.
Now, let's look at this cell containing a "⟋". It cannot be white because it has a white cell above it that would need to be mirrored on its right side if it was part of the same group.
The same principle applies to this one.
Then the cell with a "🞋" forces the group to respect a central symmetry so we must color that cell white too.
This black group cannot extend down because its right side is blocked.
The rest of the deduction is not illustrated here but here's a picture of the completed puzzle.
Here is another example puzzle to help picture various symmetries.
