No 'Check' button
'Check' counts bad cells only
'Check' highlights bad cells

Click on cells and fill the board with white or black circles. To choose the correct color follow these rules:

• No more than two of the same colour next to each other
• Each row and column must have the same number of coloured circles
• A '=' symbol between two cells means these two cells are the same
• A 'X' symbol between two cells means these two cells must be different

Guaranteed a single solution.

Best of luck!