The universe of the Game of Life is an infinite two-dimensional orthogonal grid of square cells, each of which is in one of two possible states, alive or dead. Every cell interacts with its eight neighbours, which are the cells that are horizontally, vertically, or diagonally adjacent.
At each step in time, the following transitions occur:
The initial pattern constitutes the seed of the system. The first generation is created by applying the above rules simultaneously to every cell in the seed-births and deaths occur simultaneously, and the discrete moment at which this happens is sometimes called a tick (in other words, each generation is a pure function of the preceding one). The rules continue to be applied repeatedly to create further generations. -- Wikipedia
I find the symmetric patterns to be the prettiest. It's a cool idea in any case, and I was amused to see it work so well and lifelike. After all it's based on a really simple algorithm.