I recalled an old turn-based two-player computer game where players took turns firing missiles at each other’s base. You would specify the angle of fire and the game would trace out the path of the projectile through the air as gravity pulled it down to the surface to explode. It was a two-dimensional game that would randomly seed base positions atop varying topography.
I set for myself the goal of coding this game in three dimensions. Because of my background in meteorology, I also added air resistance and random wind fields.
I had seen screenshots of three-dimensional objects created using gnuplot, but it was not until I worked on the artillery game that I was able to really see for myself the power and flexibility of the program.