Paper.io is a popular browser and mobile game where players control a colored square that leaves a trail behind it. The objective is to enclose territory on the game board by creating closed shapes with your trail. Here's a brief overview of how this snake game works:

• Gameplay: Players control a colored square that moves automatically. By changing the direction using the arrow keys or touch controls, players can guide the square to create closed shapes. Once a shape is completed, the enclosed area becomes part of the player's territory.

• Territory Expansion: The main goal in "Paper.io" is to expand your territory by enclosing as much space as possible. The more territory you control, the higher your score. However, other players can attempt to invade your territory and eliminate you by crossing your trail before it's closed.

• Competition: The game is multiplayer, so you'll be playing against other real players. The competitive aspect adds excitement and challenge as you try to outmaneuver opponents and claim territory while defending your own.