YYSL Region Sums
- Shading
- Region sum lines
The brief
Normal sudoku rules apply.
Shade some cells such that all shaded cells are orthogonally connected and all unshaded cells are orthogonally connected and no 2x2 area is fully shaded or unshaded.
Digits in caged cells indicate how many cells of the same color (shaded or unshaded) are seen orthogonally from that position, including itself. The "other" color blocks vision.
Digits along a blue line have an equal sum N within each box it passes through. If a line passes through the same box more than once, each individual segment of such a line within that box sums to N separately. Different lines may have different values for N.