the Fitbit mobile app
This is a simple wrist sized version of John Conway's Game of Life.
The Game of Life is a famous cellular automata, with rules defining the 'life' and 'death' of individual cells based on how many neighbors each cell has in each generation. A new generation is created every second.
This implementation is just a 10 x 10 matrix of cells, but like a wrist strap the field wraps around - top to bottom, left to right. So a pattern can go on forever! Just take a look at the Two Gliders or LWSS (light weight spaceship), and try out some of the other built-in patterns.
This app was created in memory of the mathematician John Conway, who passed away in 2020 due to complications from COVID-19. Please go look up his Wikipedia article or any of the other sites dedicated to his work and enjoy learning more about mathematics.