that could do all sorts of good things! So we started talking about it, figuring what would be interesting displays. We decided that probably you could make a two-dimensional maneuvering sort of thing, and decided that naturally the obvious thing to do was spaceships." Gameplay The gameplay of Spacewar! involves two monochrome spaceships called "the needle" and "the wedge", each controlled by a player, attempting to shoot one another while maneuvering on a two-dimensional plane in the gravity well of a star, set against the backdrop of a starfield. The ships fire torpedoes, which are not affected by the gravitational pull of the star. The ships have a limited number of torpedoes and supply of fuel, which is used when the player fires the ship's thrusters. Torpedoes are fired one at a time by flipping a toggle switch on the computer or pressing a button on the control pad, and there is a cooldown period between launches. The ships remain in motion even when the player is not accelerating, and rotating the ships does not change the direction of their motion, though the ships can rotate at a constant rate without inertia. Each player controls one of the ships and must attempt to shoot down the other ship while avoiding a collision with the star or the opposing ship. Flying near the star can provide a gravity assist to the player at the risk of misjudging the trajectory and falling into the star. If a ship moves past one edge of the screen, it reappears on the other side in a wraparound effect. A hyperspace feature, or "panic button", can be used as a last-ditch means to evade enemy torpedoes by moving the player's ship to another location on the screen after it disappears for a few seconds, but the reentry from hyperspace occurs at a random location, and in some versions there is an increasing probability of the ship exploding with each use. Player controls include clockwise and counterclockwise rotation, forward thrust, firing torpedoes, and hyperspace. Initially, these were controlled using the front-panel test switches on the PDP-1 minicomputer, with four switches for each player, but these proved to be awkward to use and wore out quickly under normal gameplay, as well as causing players to accidentally flip the computer's control and power switches. The location of the switches also left one player off to one side of the