Run it on turbowarp for a much larger map and much more speed: https://turbowarp.org/1187270314 Watch the different territories conquer each other. Uses a cellular automaton to approximate the outcome of battles on each cell. New territories are allowed to form on land, and territories can travel across water, but slower than on land. Each territory keeps track of it's power, which is adjusted every time it wins or loses a battle. Battles can occur on water, but don't contribute to power.
Keep watching even after a single territory takes over. It will eventually split into multiple smaller ones. I got the world map image from Vecteezy. Also the world is flat, meaning that territories can't travel from side of the screen to the other. It could be interesting to see someone remix it and program in initial territories corresponding to the countries on Earth. You could even set their power to reflect their military spending.