Author: Anurag Sahay
Divide the grid into areas of the same size such that every area contains one black and one white circle. No two identical areas (rotations and reflections included) may be orthogonally adjacent.
Grid control: To draw a cut click at the cell edge or move mouse along the line holding the button. You can also connect the cells which belong to the same area with auxiliary line. More details about grid control are at the help page.