Two inks, one sheet of paper. Red goes first, and on your turn you do one of two things.
Drop a blot
Put a blot of your ink on any blank square. It stays wet, and shiny, until you fold.
Or fold the paper
Pick a crease with the tabs around the edge. Each of your wet blots prints onto the square facing it across the crease. Tap the tab twice, or press Fold.
Wet ink smears, dry ink is set
Printed onto the other player’s wet ink, yours smears it into mud, which belongs to nobody. Dry ink never changes. After you fold, all your ink is dry.
Short folds reach less
A crease near the edge only reaches as far as the smaller side. The fold preview shades what it can’t reach.
Winning
The game ends when there’s no blank paper left. Whoever holds more squares wins. Mud counts for nobody, and a tie goes to Blue, for going second.
Why fold?
A fold can print several squares in one turn and turn the other ink to mud, and it makes your ink safe. But it uses up your turn, and while your blots wait wet, a fold from the other side can smear them.