Red Square Blue Square
- Regions to construct
- Chaos construction
The brief
- Divide the grid into ten orthogonally connected 10-cell regions.
- Each digit from 0-9 appears in one red square and one blue square, and also once in every row, column and region.
- Each region contains one red square and one blue square, whose digits sum to 9.
- A digit in an arrow cell indicates the number of borders (separating two regions) it sees in a straight line in the direction of the arrow. Borders on the outer perimeter of the grid don’t count, because they aren’t separating two regions.