Mayfield decided to create a game in the vein of "Spacewar!" that could be played on a teleprinter and brainstormed several ideas with his friends. As none of the group had much experience with computers, most of the ideas were unfeasible, but one concept he liked and thought was possible was a game based on "Star Trek", then in syndication on television. The concept included the game printing a map of the galaxy and a map of the local star system, and phaser weapons whose attack power declined over distance. Mayfield began to program the game, creating a punched tape of the game at the end of each programming session and loading it back into the computer the next day. He worked on the game through the rest of the school year and into the summer after graduating.