The classic computer simulation of Conway's Game of Life, still seems to be popular with programmers. It is not so much a game as a simulation. The action takes place of a grid with a selection of them being populated with cells. The grid is then updated to the next generation of cells. Cells make it to next generation based on a few rules such as number of neighbours. New cells can also be born. End result it a captivating pattern and repeated sequences of movement that has been used to produce music and video games.
Here's the Diving Into Dart version! Of course, it had to be colourful so cells of different ages are shaded. This still looked a bit plain so I added 4 cultures of cells to the same display. To vary things still, the number of iterations is used too and my cells are round rather than square.