Fill in the grid the numbers 1 through 9. 2.The sum of each vertical or horizontal block equals the number at the top or on the left of that block.
If the difference between two cells is 1 then there is a white dot. If digit in a cell is the half from a neighboring cell then there is a black dot. The dot between two cells with 1 and 2 can have any of these two colors. If there is no dot then neither the difference is 1 nor one cell the half of the other.