Condition

A condition is a specification of the current states of cells in some cell's neighbourhood, under some equivalence class. For example, one can write:

- 'B3' to denote the condition "the cell is currently dead and has exactly three alive neighbours and all its other neighbours are dead"

- 'S3' to denote the condition "the cell is currently alive and has exactly three alive neighbours and all its other neighbours are dead".

- The digit '3' can denote the condition "the cell has three alive neighbours and all its other neighbours are dead".

Using Hensel notation, one can write 'S4c' to denote the condition "the cell is currently alive and it has four alive neighbours, all diagonally adjacent to the cell, and four dead neighbours, all orthogonally adjacent to the cell".

This is sometimes referred to erroneously as a transition.