PenWars is a real time strategy game, where players can draw tanks using a pen-interface in a tabletop environment in order to compete against the opponent’s units. The only resource available to the players is a certain amount of digital ink for each participant, which effects the number and sizes of the units created. The tank’s properties are represented in its size and shape. A large tank for example is stronger than a smaller one, but at the same time slower and less flexible in its movements. To win the game the player has to carefully consider the properties of the opponents’ units, in connection with the map on which the game is played, when drawing his own tank units.

A typical game of PenWars starts out with two players at the opposite sides of the table. Each player has a home-base which provides a dedicated space for unit creation, bars which display the properties of the last created unit, and the amount of ink remaining. To create a new tank unit, the player has to specify the basic shape of the tanks first. This is done by drawing a closed shape inside the dedicated space. In the next step the player has to specify the shape of the tank turret drawing a line starting or ending inside the base shape. If the player is not satisfied with the outcome he can delete the unit at any stage of the creation process by crossing it out. The properties of the unit are calculated after the unit has been finalized. The player is now able to command it across the battlefield, attacking enemy units by drawing paths. When a player has used up all the ink for creating units, and all his tanks have been destroyed, the game is over.