The Conway’s Game of Life community celebrated a landmark achievement on November 9th, 2022. An idea years in the making, the “Reverse Caber Tosser” design finally had all of the pieces it needed to achieve its stated goal.

That goal is simple. Select any pattern that can be built in Life – for example, the Waterbear. Begin with a small number of gliders (now 15) in an otherwise empty Game of Life universe. After enough time goes by, those gliders need to build that pattern. No extra leftover debris, no stray scaffolding, just a pure synthesis of whatever you chose.

This post will talk about how it works, how we got there, and why it’s so cool.