Conway’s Game of Life is a game where you make an image, and then the image will mutate to a set of rules. The set up is this: You make a grid like a piece of graph paper. Each square is called a cell. A cell can be alive or dead. Any alive cell with less than 2 alive cells surrounding it dies. Any alive cell with 2 or 3 alive cells stays alive. Any alive cell with more than 3 alive cells surrounding it dies by overcrowding. Any dead cell surrounded by exactly 3 cells comes alive. Here is a Glider, a moving image:

There are pictures called Methuselahs go for a long time before making a stable pattern. Acorn goes for 5206 generations (a moment when the picture changes) before making a repitive pattern.
Here is Acorn:

Gosper’s Glider Gun (at top) makes gliders and shoots them far. Here is a link for a simulator.