Back in 2013, a Stack Exchange user posted a challenge to build a working Tetris game in Conway’s Game of Life (since Conway’s Game of Life is Turing Complete, this is possible in principle).
And four years later, a group posted what has to be one of the geekiest things I have ever come across in which they describe implementing a Tetris Processor in the Game of Life, and then writing code for that processor to play Tetris.
The underlying idea of this project is abstraction. Rather than develop a Tetris game in Life directly, we slowly ratcheted up the abstraction in a series of steps. At each layer, we get further away from the difficulties of Life and closer to the construction of a computer that is as easy to program as any other.