Patterns, Programs, and Links for Conway's Game of Life

[A Life pattern called the puffer train]

Update (11-Feb-01)

This is the new location for the Game of Life page that I began in 1995 while at Johns Hopkins. If you have a link to the old URL, I'd appreciate it a lot if you could update it. I'm cleaning up some broken links for this release. Otherwise, it is roughly where I left it in 1998. The web has exploded with Life and general cellular automata resources since I began work on this page. An excellent starting point is the Open Directory Life index, maintained by Mirek Wojtowicz.

My email address is Despite my inactivity on these pages, I still read this mail regularly and appreciate comments. I don't always remember to answer it, so send me a reminder if you don't hear from me in a couple of weeks.




Welcome to my page of odds and ends about Conway's Game of Life. This page is an on-going work, which I hope to expand regularly. This page now contains descriptions of files I have made available for ftp, links to Life resources available elsewhere on the Internet, new results and patterns not archived elsewhere, and a browsable hypertext catalog of Alan Hensel's archive of Life patterns, including a hypertext version of his Life glossary. All the patterns except those in the glossary are Java-animated, so if you have a Java-compatible browser, such as Netscape 2.0, you may want to skip right to the catalog and take a look.

I should mention that while writing this page, I have generally assumed that the reader has at least heard of the Game of Life. But if you haven't, please don't let that stand in your way. A brief explanation can already be found elsewhere on the Web.

About the Picture

Depicted at the top of the page--if you don't recognize it already--is the classic puffer train. This is what it looks like after 800 generations, or applications of Game of Life transition rules. An exact duplicate of the initial pattern can be seen at the right end of the above picture, displaced 400 cell units from where it started, near the left end of the picture. The term "puffer train" was coined to describe just this pattern, because of the way it propagates forward while leaving a trail of "smoke" behind it. Since the time of its discovery, a great many patterns have been discovered with similar properties, and the term "puffer" has come to encompass the entire class. The Life pattern used to generate this picture appears in the browsable archive below. It is called puftrain.lif.

Browsable Pattern Catalog

My illustrated catalog of Life patterns provides the most convenient way yet to browse Alan Hensel's extensive archive of Life patterns. Linked to each pattern image is a page displaying comments, and you can examine and download the entire pattern file for viewing in a Life program on your machine. Better yet, if your browser supports Java, an applet will appear and start a Life animation automatically.

Alan's comments for the patterns are often terse (well, it's an awful lot of material to document) and use a rather specialized terminology. You may wish to refer to the illustrated glossary adapted from the one that Alan provided in his distribution A text version of the glossary is provided for those who are using a text-only browser, or who do not have a fast connection. For an even more comprehensive list of Life terms, see Stephen Silver's lexicon.

Selected Topics

These links delve into the theory, operation, or design history of Life patterns and whole classes of patterns. The format is mixed and includes articles I've written for the page, as well as mail digests and contributed articles. In contrast to the pattern catalog, the emphasis here is on verbal explanation. Numerous patterns are nonetheless included as examples, and can be viewed in the applet or downloaded as ASCII files. Dates denote time of addition to this page.

Resource List

Since about 1990, I have been using the Internet regularly to communicate with others interested in Conway's Game of Life. The introduction of the World Wide Web protocol and the current availability of browsers has greatly enhanced the Internet's potential for this purpose. The following list contains those Web resources best known to me, along with a brief description. The list is presented roughly in order, starting with what is readily accessible and fun for the novice, and progressing towards the more specialized and esoteric:

Other Game of Life Pages

A great place to start looking for Game of Life information is the Open Directory Life index. Here's my own random smattering of related links.

Additional Resources

Here is a sampling of related resources. I have not had the time to keep this list up to date ever since starting it in 1995. However, I am confident that starting here, almost everything can be found just a few links away.

Programs that can read patterns in Alan Hensel's archive

Artificial Life Resources

It is the source of much, occasionally rancorous, debate as to whether Conway's Game of Life and the field of artificial life have anything to do with one another, apart from the somewhat coincidental name correspondence. Both involve the study of complex, seemly unpredictable systems, so the connection is not entirely arbitrary. In any case, the following resources are in themselves interesting, and may help you find additional resources related to the Game of Life.


The above links were contributed by Alan Hensel, Joerg Heitkoetter, and David Griffeath.

Off-line Resources

Not everything to do with the Game of Life can be found on the Internet, at least not yet. Alan Hensel has compiled a bibliography of books and articles on the Game of Life.
This page is maintained by Paul Callahan (last update: 11-Feb-01).