Naturally, I decided to try to write my own computer games. There were several of these, but a perennial favourite among my friends was one of the simpler ones, dubbed "Kill the Cities". In this game, you would be presented with a 3 × 3 array of red and green rectangles, which were the "cities". You had a crosshair to aim with, which you could move about the screen, and push the "fire" button to shoot. You had unlimited time, unlimited ammunition, the cities didn't move, didn't have shields, and didn't shoot back. A single shot within its boundaries would destroy a city. If, under these difficult conditions, you actually managed to wipe out all the cities, the game would print out "You win! You hear that? They're CHEERING for you!", accompanied by a hissing noise.
As I wasn't yet expert at dealing with graphics, there was a bug in the game that some found more entertaining than the game itself: the crosshair would erase the cities as it moved about, so a player could eventually render all the cities invisible. This made the game even more challenging!