Artillery games are two or three-player (usually turn-based) video games involving tanks (or simply cannons) trying to destroy each other. The core mechanics of the gameplay is almost always to aim at the opponent(s) following a ballistic trajectory (in its simplest form, a parabolic curve). Artillery games are among the earliest computer games developed; the theme of such games is an extension of the original uses of computer themselves, which were once used to calculate the trajectories of rockets and other related military-based calculations. Artillery games have been described as a type of "shooting game", though they are more often classified as a type of strategy video game. Early precursors to the modern artillery-type games were text-only games that simulated artillery entirely with input data values. One of the earliest known games in the genre is War 3 for two or three players, written in FOCAL Mod V by Mike Forman (date unknown). The game was then ported to TSS/8 BASIC IV by M. E. Lyon Jr. in 1972. Ported again to HP Time-Shared BASIC by Brian West in 1975. And, finally, to a cross-platform subset of Microsoft BASIC by Creative Computing in 1979 for the book More BASIC Computer Games where it appears with multiple names: Artillery-3, Artillery 3, and WAR3. Another early game is Gunner (1973) by Tom Kloos. These early versions of turn-based tank combat games interpreted human-entered data such as the distance between the tanks, the velocity or "power" of the shot fired and the angle of the tanks' turrets. List of artillery video games The Tektronix 4051 BASIC language desktop computer of the mid-1970s had a demo program called Artillery which used a storage-CRT for graphics. A similar program appeared on the HP 2647 graphics terminal demo tape in the late 1970s. Graphical adaptions of the artillery game, such as Super Artillery and Artillery Simulator, emerged on the Apple II computer platform in 1980.