Twigs
Sample 9x9
Place 2 pigs in every row, column and pen. Pigs may not touch, not even diagonally.
Paused
Click a square to cross it out (no pig there), or press and drag to cross out several. Double-click to place a pig. Once every pig is placed, your answer is checked automatically. The timer pauses whenever you leave the page; press Continue to carry on. Your progress and time are saved in this browser.