Life Credits

David Buckingham

David Buckingham significantly expanded the lists of known still-lifes, first listing the 12-bits (simultaneously with Petrie and Boyer), first listing the 13-bits, and using Raynham's search program to first list the 14-bits.

He found many oscillators, including literally hundreds of billiard-table configurations, as well as a basic puffer train.

He developed most of the existing technology used in glider synthesis of still-lifes, oscillators, and spaceships, and methodically generated syntheses of all still-lifes and oscillators up to 14 bits, as well as many larger ones.

In 1996, he revealed a suite of track components which use eaters and other still-lifes to move can move a Herschel heptomino (the 20th generation of B-heptomino, after it has left behind a block). By combining several of these, in much the same way as one assembles toy train tracks, one can produce circular conduits which take arbitrarily long to cycle a single Herschel. By placing multiple Herschels in such a conduit, one can obtain oscillators of arbitrarily small periods. (These were improvements over his earlier track components which used spark-producing oscillators as stabilizers; unfortunately, those can only produce oscillators whose periods are multiples of those of the spark-producers.)

Oscillators of all periods 58 and above can be obtained in this way. Since Herschels naturally release gliders, this also yields glider guns of all periods 62 and above. (The Herschels collide with each other if closer than 58 generations apart, and they collide with the escaping gliders if closer than 62 generations apart.) Recently, Dietrich Leithner has constructed oscillators of periods 57 and 56 by adding in one of Buckingham's earlier spark-stabilized sections.

This is basically a variation of the method described by Conway in the 1970's to construct oscillators of arbitary period using stable glider-reflectors. (Currently, all known stable glider-reflectors are derived from the above, turning a glider into a Herschel, shuttling the Herschel, and then turning the Herschel back into a glider.)

Paul Callahan

Paul Callahan has expanded Buckingham's Herschel conduit mechanisms, building stable glider reflectors.

He has also maintains a web page which includes a compreshensive Life pattern catalog, and a Java Life applet.

Tim Coe

Tim Coe found the period-16 puffer engine, which is itself a clean spaceship, but which has easily ignitable exhaust, facilitating construction of many puffer trains.

He has also recently discovered a new small P8 oscillator, and a collision of 11 gliders which which eventually produces a natural Caterer.

John Horton Conway

In the early 70's, John Horton Conway invented the Game of Life. He did much of the original research into Life, laying most of the game's basic mathematical foundations.

He found many of the small still-lifes, oscillators (including the Pulsar and Pentadecathlon), and spaceships (Glider, Light-weight spaceship (LWSS), Middle-weight spaceship (MWSS), and Heavy-weight spaceship (HWSS).)

Noam Elkies

Noam Elkies has found several oscillators, including the period-36 Two eaters hassling two T-tetrominos, a new period-5 oscillator, and the infinitely-expandable Traffic-Jam oscillators.

He has also proven that the density of Life still-lifes cannot exceed 50%.

Achim Flammenkamp

Achim Flammenkamp performed many experiments on random Life fields, collecting statistics on object artificiality. In the process, he found many never-before-seen naturally-occuring (though extremely rare) oscillators, such as the Dual 1-2-3-4, the P5 Pseudo barber-pole, the P8 Smiley, a P16, and a P144.

His results are available on his web page.

R. William Gosper

Bill Gosper found some of Life's basic shuttle-based oscillators, including Queen Bee, Twin Bees, and Centinal. He first proved that Life patterns could expand forever by constructing the first glider gun, and subsequently puffer trains. He subsequently also proved that Life patterns could expand quadratically by constructing the first breeder, by having a flotilla of puffers which construct glider guns.

Dean Hickerson

Dean Hickerson wrote the first oscillator search program, which found many new oscillators, including some small ones like the Caterer, Mold, and Jam. This program also found the first spaceships other than the natural ones found by Conway. He has recently written another search program which has found many new billiard-table oscillators, including the first period 17.

He also found glider syntheses of several large objects which occur naturally in contrived situations, as well as the first four-glider synthesis of the Tub w/tail.

H. Koenig

H. Koenig has performed many computer object searches, verifying Buckingham's and Niemiec's still-life counts up to 18 bits, and period 2 oscillators up to 16 bits, (as well as making several minor corrections to some of these lists.)

He has also collected statistics on many randomly-occuring Life objects and oscillators, the results of which have resulted in improved glider syntheses of some of these.

He has recently found a previously-unknown three-glider synthesis of the Pentadecathlon.

He maintains a web page which includes lists of objects and many glider syntheses, an alternative to the information contained here.

Mark D. Niemiec

Mark D. Niemiec has found several oscillators, including the period-9 Snacker.

He expanded on Buckingham's enumeration results, generating complete lists of still-lifes and pseudo-still-lifes up to 24 bits, as well as period-2 oscillators and pseudo-oscillators up to 19 bits. He has also listed larger-period oscillators and pseudo-oscillators up to 20 bits by hand, although these still await computer verification.

He has expanded on Buckingham's glider synthesis results, generating syntheses of many 15-bit still-lifes, all pseudo-still-lifes up to 15 bits, many remaining period 2 oscillators of 15-18 bits, most period 2 pseudo-oscillators up to 19 bits, and most higher-period oscillators and pseudo-oscillators up to 20 bits. Niemiec is also the author and maintainer of these Life pages, which show many of the above object lists and syntheses.

Douglas G. Petrie

Douglas G. Petrie found many early glider syntheses, including the Toad, Half-fleet (12.3), Pulsar, Pentadecathlon, HWSS, Schick ship, and Switch engine.

He and V. Everett Boyer also first listed the 12-bit still-lifes, (simultaneously with Buckingham).

Peter R. Raynham

Peter R. Raynham has found several small oscillators.

He also found several glider syntheses, including a 14-bit still-life Sidewalk (14.507), and the previous optimal (for twenty years) four-glider synthesis of the Pentadecathlon.

He wrote the first program to search for still-lifes, verifying the lists created by Wainwright and Buckingham, and which Buckingham used to expand the state of the art to include the 14-bit still-lifes.

Robert T. Wainwright

In the early 70's, Robert T. Wainwright published Lifeline, a newsletter devoted to discoveries about Life, and sometimes other similar cellular automata. Many of the original discoveries in Life were first published in Lifeline, and Lifeline served to foster much interest in Life, which was then still in its infancy.

Wainwright began the first efforts to systematically list the still-lifes, assembling lists up to 11 bits from various partial lists submitted by various Lifeline readers.

He also found many oscillators, including blocker, and a basic puffer train.

Miscellaneous

John Abbott found the first glider synthesis of a long boat.

George D. Collins, Jr. discovered the period-14 oscillator tumbler.

Charles Corderman discovered the 9-bit still-life hat and three variants of the switch engine (block-making, glider-making, and Noah's ark) the only known naturally-occurring puffer train.

Sol Goodman and Arthur C. Taber discovered the period-5 oscillator octagon-II.

Alan Hensel maintains a web page which includes a comprehensive glossary of Life patterns and terms.

Jan Kok discovered the period-8 oscillator Kok's Galaxy.

Clement A. Lessner III and William P. Webb discovered the 7-bit still life eater.

D. R. McEntee found the synthesis of the 14-bit still-life Bookend tie bookend (14.582).

Richard Schroeppel discovered the period-3 oscillator Cuphook.

Paul Schick discovered a clean puffer-train tag-along, the Schick ship.

Stephen Silver reduced by one glider Buckingham's 5-glider mechanism for adding a table, reducing the cost of several still-lifes which include tables, such as 14.446 and 14.448.

In 1986, Andrew Trevorrow discovered Rabbits, one of the most prolific metheuselahs.

Don Woods discovered a period-8 billiard table Cauldron.

See also: definitions, structure, credits.

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