Normal sudoku rules apply. Shade some cells such that all shaded cells are orthogonally connected and all unshaded cells are orthogonally connected. No 2x2 area may be fully shaded or fully unshaded. Along a line, any changes in shading divide that line into segments of fully shaded or fully unshaded cells. On each line, each such segment (shaded or unshaded) must have the same sum as all other segments. Within the shaded areas, adjacent digits along the lines must differ by at least 5. Within unshaded areas, any string of 3 or fewer digits along the lines must be from a different set of (147), (258) and (369).