Conway’s Game of Life

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Life Lexicon

Bistable switch

A Spartan memory cell found by Paul Callahan in 1994. It can be in one of two states, containing either a boat or a block. Input gliders on the appropriate paths can change the boat to a block, or vice-versa, while also emitting an output glider. Unlike many memory cells, attempts to change the state to the one it is already in are ignored with the glider passing through with no reaction. This makes it easy to reset the memory cell to a known state. Which of the two states is considered the SET and which considered the RESET is just a matter of convention.

The pattern below shows the "boat" state of the memory cell in its original 1994 form. Two gliders are also shown to indicate the input paths used to change the states. A smaller version is shown under century eater, with the circuit in its "block" state.

As shown, the rightmost glider changes the state from a boat to a block and emits a glider to the upper right, while the leftmost glider passes through unchanged. Alternatively, when the state contains a block, then the leftmost glider changes the state from a block to a boat, and emits a glider to the lower right, while the rightmost glider passes through unchanged.

Game of Life pattern ’bistable_switch’

Game of Life Explanation

The Game of Life is not your typical computer game. It is a cellular automaton, and was invented by Cambridge mathematician John Conway.

This game became widely known when it was mentioned in an article published by Scientific American in 1970. It consists of a grid of cells which, based on a few mathematical rules, can live, die or multiply. Depending on the initial conditions, the cells form various patterns throughout the course of the game.

Rules

For a space that is populated:
Examples

Each cell with one or no neighbors dies, as if by solitude.

Each cell with four or more neighbors dies, as if by overpopulation.

Each cell with two or three neighbors survives.

For a space that is empty or unpopulated:

Each cell with three neighbors becomes populated.

More information

Video’s about the Game of Life

Stephen Hawkings The Meaning of Life (John Conway's Game of Life segment)
The rules are explained in Stephen Hawkings’ documentary The Meaning of Life
Inventing Game of Life (John Conway) - Numberphile
John Conway himself talks about the Game of Life

Interesting articles about John Conway

Implemented by Edwin Martin <>