Flip was created as a game to play in class just using pencil and paper for my friends and me to challenge and entertain ourselves while escaping from the doldrums of a boring lecture. Each of us would try and make very difficult levels to stump the rest of the group.
Select filled in tiles and chose a direction to "flip" them to fill in the empty space. Your goal is to fill all the empty spaces in as few moves as possible, but don't land on the "negative" spaces! If you've filled the whole level with the required number of flips you've completed it, just don't go over!