To solve you need to mark all the blank cells either black or white according to the following three rules:
• There are the same number of black and white cells in each row and column.
• No more than two adjoining cells (either horizontally or vertically) can be the same color.
• Each row is unique, and each column is unique.
Each time you left click or tap a cell, the value will cycle through WHITE, BLACK and then blank.
Alternatively you can right click to set a cell BLACK.