A methuselah is, roughly speaking, a pattern that takes a large number of generations in order to stabilize (known as its lifespan) and becomes much larger than its initial configuration at some point during its evolution. In particular, patterns that grow forever are not methuselahs. Their exact definition is not completely agreed upon, and most definitions place restrictions on the number of cells in the initial pattern.
The smallest methuselah is the R-pentomino, a pattern of five cells first considered by John Conway that takes 1103 generations before stabilizing. The acorn, a pattern of seven cells developed by Charles Corderman, takes 5206 generations to stabilize. Some other popular examples include B-heptomino, bunnies, die hard and rabbits.
The longest-lived methuselah known to date, 40514M, was discovered by knightlife. It has an initial population of 18, a final population of 3735, takes 40514 generations to stabilize, and fits within a 78×54 bounding box.
- Gardner, M. (1983). "The Game of Life, Part III". Wheels, Life and Other Mathematical Amusements: 246, W.H. Freeman.
- Gardner, M. (1983). "The Game of Life, Part III". Wheels, Life and Other Mathematical Amusements: 219, 223, W.H. Freeman.
Methuselah at the Life Lexicon