An object that moves like a spaceship, except that it leaves
debris behind. The first known puffers were found by Bill Gosper and
travelled at c/2 orthogonally (see diagram below for the very first
one, found in 1971).
Not long afterwards c/12 diagonal puffers were found (see
switch engine). Discounting wickstretchers, which are not
puffers in the conventional sense, no new velocity was obtained after
this until David Bell found the first c/3 orthogonal puffer in April
1996. Other new puffer speeds followed over the next several years.
Many spaceships that travel orthogonally at a speed less than c/2
have useful side or back sparks. These can be used to perturb
standard spaceships that approach from behind. A common technique
for creating puffers for a new speed uses a convoy of the new
spaceships to create debris from an approaching standard spaceship
such that a new standard spaceship is recreated on the same path as
the original one. This forms a closed loop, resulting in a
high-period puffer for the new speed.
As of June 2018, puffers have been found matching every known
velocity of elementary spaceship, except for c/6 and c/7 diagonal
and (2,1)c/6. It is also generally easy to create puffers based on
macro-spaceships, simply by removing some part of the trailing
cleanup mechanism.
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.
These are services I personally use and trust every day.
These links are affiliate links, which means I
may earn a commission if you choose to make a purchase—at no extra cost to
you. This helps support this site and allows me to continue improving it.
Thank you for your support!
Fastmail - Good, private email hosting for yourself, your familiy or business.
Backblaze - Reliable and user friendly cloud backup for your computer.