Switch off all the buildings lights by touching its windows.
For each window you touch, you change its state (from on to off or from off to on) and its adjacent windows (up, down, left and right) either, so think wisely!
Switch off all the buildings lights by touching its windows.
For each window you touch, you change its state (from on to off or from off to on) and its adjacent windows (up, down, left and right) either, so think wisely!