I can recommend the recent book "Conway's Game of Life: Mathematics and Construction" (downloadable free at https://conwaylife.com/book/ https://conwaylife.com/

I can recommend the recent book "Conway's Game of Life: Mathematics and Construction" (downloadable free at https://conwaylife.com/book/ https://conwaylife.com/book/), it starts gently and builds up to these kind of constructions (minus what has been discovered in the last year or so).