lecicon.diff:
Code: Select all
2c2
< Release 25, 2006 February 28
---
> Release 26, 2007 April ? (unfinished)
39c39
< This lexicon is copyright (C) Stephen Silver, 1997-2005. It may be
---
> This lexicon is copyright (C) Stephen Silver, 1997-2006. It may be
161a162,185
> :17c/45 spaceship: A {spaceship} travelling at seventeen forty-fifths
> of the {speed of light}. This is the strangest spaceship speed for
> which there is any known example. See {Caterpillar} for details.
>
> :2c/5 spaceship: A {spaceship} travelling at two fifths of the
> {speed of light}. The only such spaceships that are currently known
> travel orthogonally. The first was found by Dean Hickerson in July
> 1991, and is shown below.
> ...***...***...
> ...*.*...*.*...
> .*...*...*...*.
> .*..*.....*..*.
> .**.**...**.**.
> ...***...***...
> .....**.**.....
> **..***.***..**
> .*..***.***..*.
> .*..**...**..*.
>
> :2c/7 spaceship: A {spaceship} travelling at two sevenths of the
> {speed of light}. The only such spaceships that are currently known
> travel orthogonally. The first to be found was the {weekender},
> found by David Eppstein in January 2000.
>
437c461
< Holzwart in September 2004.
---
> Holzwart in April 2004.
1040a1065,1066
> :bobsled: See {switch engine channel}.
>
1252a1279,1362
> :c/12 spaceship: A {spaceship} travelling at one twelfth of the
> {speed of light}. The only such spaceships that are currently
> known are the {Cordership}s.
>
> :c/2 spaceship: A {spaceship} travelling at half the {speed of light}.
> Such spaceships necessarily move orthogonally. The first to be
> discovered was the {LWSS}. For other examples see {Coe ship},
> {ecologist}, {flotilla}, {hammerhead}, {hivenudger}, {HWSS},
> {MWSS}, {puffer train}, {puff suppressor}, {pushalong},
> {Schick engine}, {sidecar}, {still life tagalong} and {x66}.
>
> :c/3 spaceship: A {spaceship} travelling at one third of the
> {speed of light}. All known c/3 spaceships travel orthogonally,
> and the first was found in August 1989 by Dean Hickerson. For
> further examples see {brain}, {dart}, {edge-repair spaceship}, {fly},
> {turtle} and {wasp}. A spaceship moving diagonally at an angle of
> 45 degree cannot travel at a speed of c/3, but it is likely that c/3
> {knightship}s exist, though none have yet been found.
>
> :c/4 spaceship: A {spaceship} travelling at one quarter of the
> {speed of light}. The first such spaceship to be discovered was,
> of course, the {glider}, and this remained the only known example
> until December 1989, when Dean Hickerson found the first orthogonal
> example and also a new diagonal example (the {big glider}).
> For other examples see {B29}, {Canada goose}, {crane}, {Enterprise},
> {edge-repair spaceship}, {non-monotonic}, {Orion}, {quarter},
> {sparky}, {swan} and {tagalong}. It is known that c/4 is the fastest
> possible speed for a (45-degree) diagonal spaceship.
>
> :c/5 spaceship: A {spaceship} travelling at one fifth of the
> {speed of light}. The first such spaceship to be discovered was the
> {snail}, found by Tim Coe in January 1996. The first diagonally
> moving example was found by Jason Summers in November 2000. In
> January 2005, Summers found the smaller diagonal specimen shown
> below.
> ..........**..........
> .........*..*.........
> ........**............
> .........*.**.........
> ..........*.***.......
> ..........**.***......
> ............*....**...
> ............***....**.
> ..*.........*.*.......
> .***........*..*......
> *...**................
> *..*.*.......**.*..*..
> .*.**.****...*...****.
> ....**.*...**.......*.
> ....**.**..*.........*
> .....*...*........*.**
> ...........*.......*..
> ......*.....*......*..
> ......*.....*..*......
> .......*...**...**....
> .......*....**.*......
> ..............**......
>
> :c/6 spaceship: A {spaceship} travelling at one sixth of the
> {speed of light}. The first such spaceship to be discovered was the
> {dragon}, found by Paul Tooke in April 2000. The first diagonally
> moving example was the {seal}, found by Nicolay Beluchenko in
> September 2005. Another orthogonal c/6 spaceship, found by Paul
> Tooke in March 2006, is shown below.
> ..*..............*..................................*.....
> *..*..***.......*.****...............**...........**.*....
> *..*............***.*.*.........*.....*.......*...*.......
> .*.*..*.....................***..*.*.***.....*.*.*....*...
> ..**......*....*................******..*..*...*...*..*...
> .*.*...**.....*...**......**.**..*..**..*.*.**..*.........
> ..*.....*.**..*...**......**....*.*.*..*..*.*.*......**..*
> ..*....***..*.........***.......***.*.**.....*.......***.*
> ............*********...*........**.***...****.........*.*
> ..........................................................
> ............*********...*........**.***...****.........*.*
> ..*....***..*.........***.......***.*.**.....*.......***.*
> ..*.....*.**..*...**......**....*.*.*..*..*.*.*......**..*
> .*.*...**.....*...**......**.**..*..**..*.*.**..*.........
> ..**......*....*................******..*..*...*...*..*...
> .*.*..*.....................***..*.*.***.....*.*.*....*...
> *..*............***.*.*.........*.....*.......*...*.......
> *..*..***.......*.****...............**...........**.*....
> ..*..............*..................................*.....
>
1359,1364c1469,1475
< {metacatacryst}. The catacryst consists of three {ark}s plus a
< glider-producing {switch engine}. It produces a block-laying switch
< engine every 47616 generations. Each block-laying switch engine has
< only a finite life, but the length of this life increases linearly
< with each new switch engine, so that the pattern overall grows
< quadratically, as an unusual type of MMS {breeder}.
---
> {metacatacryst}, and later by {Gotts dots} and {wedge}. The catacryst
> consists of three {ark}s plus a glider-producing {switch engine}. It
> produces a block-laying switch engine every 47616 generations. Each
> block-laying switch engine has only a finite life, but the length of
> this life increases linearly with each new switch engine, so that
> the pattern overall grows quadratically, as an unusual type of MMS
> {breeder}.
1733c1844
< 46 and 60 to replace the {Kok's galaxy}.
---
> 46 and 60 that can be used instead of the {Kok's galaxy}.
2246,2248c2357
< Paul Tooke in April 2000, was the first known c/6 spaceship.
< All other known orthogonal c/6 spaceships are {flotilla}s involving
< at least two dragons.
---
> Paul Tooke in April 2000, was the first known {c/6 spaceship}.
2433c2542
< useful examples are the following two small p3 c/3 spaceships:
---
> useful examples are the following two small p3 {c/3 spaceship}s:
2454c2563
< a c/4 spaceship can also be self-repairing. Stephen Silver noticed
---
> a {c/4 spaceship} can also be self-repairing. Stephen Silver noticed
3030,3031c3139,3140
< also a frequent contributor to the blog, which can be found at
< {http://gameoflife-news.blogspot.com}.
---
> also a frequent contributor to the blog, which can be found at
> {http://pentadecathlon.com/lifeNews/index.php}.
3290,3292c3399,3401
< March 2003 that Summers and Elkies managed to find a way perform the
< crucial last step. Summers then used the new synthesis to build a
< c/2 forward rake for the 2c/5 spaceship; this was the first example
---
> March 2003 that Summers and Elkies managed to find a way to perform
> the crucial last step. Summers then used the new synthesis to build
> a c/2 forward rake for the 2c/5 spaceship; this was the first example
3309,3311c3418,3451
< :glider train: A certain {puffer} that produces two rows of {block}s
< and two backward {glider} waves. Ten of these were used to make the
< first {breeder}.
---
> :glider train: A certain p64 c/2 orthogonal {puffer} that produces two
> rows of {block}s and two backward {glider} waves. Ten of these were
> used to make the first {breeder}.
> ..............................*............
> ...............................*...........
> .........................*.....*...........
> ....*.....................******.....******
> .....*..............................*.....*
> *....*....................................*
> .*****..............................*....*.
> ......................................**...
> ...........................................
> .....................................*.....
> ....................................*......
> ...................................**...**.
> ...................................*.*...**
> ....................................*...**.
> ........................................*..
> ...........................................
> ........................................*..
> ....................................*...**.
> ...................................*.*...**
> ...................................**...**.
> ....................................*......
> .....................................*.....
> ...........................................
> ......................................**...
> .*****..............................*....*.
> *....*....................................*
> .....*..............................*.....*
> ....*.....................******.....******
> .........................*.....*...........
> ...............................*...........
> ..............................*............
3372a3513,3521
> :Gotts dots: A 41-cell pattern with superlinear (but not quadratic)
> growth. In terms of initial population, this is the smallest known
> pattern with superlinear growth. It was found in March 2006 by
> Bill Gosper, who named it in honour of Nick Gotts (discoverer of
> many other low-population superlinear patterns, such as {Jaws},
> {mosquito}s, {teeth}, {catacryst} and {metacatacryst}). The
> population of the pattern at time t is asymptotically proportional
> to t.log(t).
>
3432,3434c3581,3584
< :grey ship: A {spaceship} that contains a region with a density of 1/2,
< and which is {extensible} in such a way that the region of density
< 1/2 can be made larger than any given square region.
---
> :grey ship: A {spaceship} that contains a region with an average
> density of 1/2, and which is {extensible} in such a way that the
> region of average density 1/2 can be made larger than any given
> square region.
3501c3651
< :hammerhead: A certain front end for c/2 spaceships. The central
---
> :hammerhead: A certain front end for {c/2 spaceship}s. The central
3572,3586c3722,3734
< advantage of the considerable amount of repetitive behaviour in many
< large patterns of interest. This algorithm is described by Gosper
< in his paper listed in the bibliography at the end of this lexicon.
< Roughly speaking, the idea is to store subpatterns in a hash table so
< that the results of their evolution do not need to be recomputed if
< they arise again at some other place or time in the evolution of the
< full pattern. This does, however, mean that complex patterns can
< require substantial amounts of memory.
< Hashlife provides a means of evolving repetitive patterns millions
< (or even billions or trillions) of generations further than normal
< Life algorithms can manage in a reasonable amount of time. It is
< not, however, suitable for showing a continuous display of the
< evolution of a pattern, because it works asynchronously - at any
< given moment it will usually have evolved different parts of the
< pattern through different numbers of generations.
---
> advantage of the considerable amount of repetitive behaviour in
> many large patterns of interest. It provides a means of evolving
> repetitive patterns millions (or even billions or trillions) of
> generations further than normal Life algorithms can manage in a
> reasonable amount of time.
> The hashlife algorithm is described by Gosper in his paper listed
> in the bibliography at the end of this lexicon. Roughly speaking,
> the idea is to store subpatterns in a hash table so that the results
> of their evolution do not need to be recomputed if they arise again
> at some other place or time in the evolution of the full pattern.
> This does, however, mean that complex patterns can require
> substantial amounts of memory.
> See also {Golly}.
4085,4086c4233,4234
< common {spaceship}. Found by Conway in 1970. See also {LWSS} and
< {MWSS}.
---
> common {spaceship}. Found by Conway in 1970 by modifying a {LWSS}.
> See also {MWSS}.
4208c4356,4357
< {sawtooth}s and a {caber tosser}.
---
> {sawtooth}s and a {caber tosser}. Another pattern with superlinear
> but non-quadratic growth is {Gotts dots}.
4328c4477
< {catacryst} and {metacatacryst}.
---
> {catacryst}, {metacatacryst}, {Gotts dots} and {wedge}.
4574a4724,4726
> :line-cutting reaction: A reaction that can cut an infinite diagonal
> line of cells, leaving a gap with both ends sealed.
>
4808,4809c4960,4961
< (after the {glider}). Found by Conway in 1970. See also {MWSS}
< and {HWSS}.
---
> (after the {glider}). Found by Conway when one formed from a random
> soup in 1970. See also {MWSS} and {HWSS}.
4865,4866c5017,5019
< by Nick Gotts, December 2000. This is currently the smallest known
< pattern (in terms of initial population) with superlinear growth.
---
> by Nick Gotts, December 2000. This was for some time the smallest
> known pattern (in terms of initial population) with superlinear
> growth, but has since been beaten by {Gotts dots} and {wedge}.
5054,5055c5207,5208
< growth, but it has since been superseded by {teeth}, {catacryst} and
< {metacatacryst}.
---
> growth, but it has since been superseded by {teeth}, {catacryst},
> {metacatacryst}, {Gotts dots} and {wedge}.
5100,5101c5253,5254
< most common {spaceship}. Found by Conway in 1970. See also {LWSS}
< and {HWSS}.
---
> most common {spaceship}. Found by Conway in 1970 by modifying a
> {LWSS}. See also {HWSS}.
5535a5689,5716
>
> :p72 quasi-shuttle: The following {oscillator}, found by Jason Summers
> in August 2005. Although this looks at first sight like a {shuttle},
> it isn't really.
> ..............................*......
> .............................**......
> ............................*.**.....
> .****......................***..*....
> *....*.......................*.*.*...
> *...*.*.......................*.*.*..
> .*...*.*......**...............*..***
> .......*.....*.*................**.*.
> .......*.....*...................**..
> ....*..*.....***.................*...
> .....**..............................
> .....................................
> .....**..............................
> ....*..*.....***.................*...
> .......*.....*...................**..
> .......*.....*.*................**.*.
> .*...*.*......**...............*..***
> *...*.*.......................*.*.*..
> *....*.......................*.*.*...
> .****......................***..*....
> ............................*.**.....
> .............................**......
> ..............................*......
>
5674c5855
< :phase change: A {perturbation} of a periodic object which causes the
---
> :phase change: A {perturbation} of a periodic object that causes the
6060a6242,6243
> :PRNG: = {pseudo-random number generator}
>
6102,6110c6285,6301
< :pseudo-random glider generator: An object which emits a random-looking
< stream of {glider}s, like the sequence of bits from a pseudo-random
< number generator. Pseudo-random glider generators contain gliders
< or other {spaceship}s in a loop with a feedback mechanism which
< causes later spaceships to interfere with the generation of earlier
< spaceships. The {period} can be very high, since a loop of n
< spaceships has 2^n possible states.
< The first pseudo-random glider generator was built by Bill Gosper.
< David Bell built the first moving one in 1997, using c/3 {rake}s.
---
> :pseudo-random glider generator: A {pseudo-random number generator}
> in which the bits are represented by the presence or absence of
> {glider}s. The first pseudo-random glider generator was built by
> Bill Gosper. David Bell built the first moving one in 1997, using
> c/3 {rake}s.
>
> :pseudo-random number generator: A pseudo-random number generator
> (PRNG) is an algorithm that produces a sequence of bits that
> looks random (but cannot really be random, being algorithmically
> determined).
> In Life, the term refers to a PRNG implemented as a Life pattern,
> with the bits represented by the presence or absence of objects such
> as {glider}s or {block}s. Such a PRNG usually contains gliders or
> other {spaceship}s in a loop with a feedback mechanism that causes
> later spaceships to interfere with the generation of earlier
> spaceships. The {period} can be very high, as a loop of n spaceships
> has 2^n possible states.
6177a6369,6383
> In April 2006, Jason Summers found a way to make the classic puffer
> train into a p20 {spaceship} by adding a {glider} at the back:
> ***...........***.
> *..*..........*..*
> *......***....*...
> *.....*..*....*...
> .*.*..*...*....*.*
> .......****.......
> .........*........
> ..................
> ..................
> ..................
> .......***........
> .......*..........
> ........*.........
6401c6607,6609
< by Jason Summers in September 2000. See also {tubstretcher}.
---
> by Jason Summers in September 2000. This is the smallest known
> {c/4 spaceship} other than the {glider}. This spaceship can also be
> used to make the smallest known {tubstretcher}.
6491,6492c6699,6700
< and less symmetric {stator} discovered by Noam Elkies in August
< 1994. Compare with {Gray counter}.
---
> and less symmetric {stator} found by Noam Elkies in August 1994.
> Compare with {Gray counter}.
6752c6960
< time it has a {population} of 116.
---
> time it has a {population} of 116, including six {glider}s.
6766c6974,6975
< (sequence A001511 in The On-Line Encyclopedia of Integer Sequences).
---
> (sequence A001511 in The On-Line Encyclopedia of Integer Sequences:
> {http://www.research.att.com/~njas/sequences/A001511}).
6870c7079
< :seal: (c/6 diagonally, p6) The first c/6 diagonal {spaceship}, found
---
> :seal: (c/6 diagonally, p6) The first diagonal {c/6 spaceship}, found
7285,7286c7494
< An end can also be stabilized by killer {candlefrobra}s, although
< this isn't efficient.
---
> An end can also be stabilized by killer {candlefrobra}s.
7288c7496
< :snail: (c/5 orthogonally, p5) The first known c/5 {spaceship},
---
> :snail: (c/5 orthogonally, p5) The first known {c/5 spaceship},
7453,7460c7661,7664
< {LWSS}, {MWSS} and {HWSS}. For further examples see {B29},
< {big glider}, {brain}, {Canada goose}, {Coe ship}, {Cordership},
< {crane}, {dart}, {dragon}, {ecologist}, {edge-repair spaceship},
< {Enterprise}, {flotilla}, {fly}, {hammerhead}, {hivenudger},
< {non-monotonic}, {Orion}, {puff suppressor}, {pushalong}, {quarter},
< {Schick engine}, {seal}, {sidecar}, {snail}, {still life tagalong},
< {sparky}, {swan}, {turtle}, {wasp}, {weekender} and {x66}. See also
< {Caterpillar}.
---
> {LWSS}, {MWSS} and {HWSS}. See also the entries on individual
> spaceship speeds: {c/12 spaceship}, {c/6 spaceship},
> {c/5 spaceship}, {c/4 spaceship}, {2c/7 spaceship}, {c/3 spaceship},
> {17c/45 spaceship}, {2c/5 spaceship} and {c/2 spaceship}.
7492,7515d7695
< The following diagram shows one of only two known c/5 diagonal
< spaceships. It was found by Jason Summers in January 2005.
< ..........**..........
< .........*..*.........
< ........**............
< .........*.**.........
< ..........*.***.......
< ..........**.***......
< ............*....**...
< ............***....**.
< ..*.........*.*.......
< .***........*..*......
< *...**................
< *..*.*.......**.*..*..
< .*.**.****...*...****.
< ....**.*...**.......*.
< ....**.**..*.........*
< .....*...*........*.**
< ...........*.......*..
< ......*.....*......*..
< ......*.....*..*......
< .......*...**...**....
< .......*....**.*......
< ..............**......
7571c7751
< speed at which any effect can propagate.
---
> speed at which any effect can propagate. Usually denoted c.
7581c7761
< {puffer}s, including {rake}s. See also {pre-pulsar}.
---
> {puffer}s, including {rake}s. See also {PPS}.
7657,7658c7837,7841
< This is not necessarily well-defined, because the eater may have more
< than one eating action.
---
> This is not always well-defined, because an eater can have more than
> one eating action.
>
> :statorless: A statorless {oscillator} is one in which no cell is
> permanently on - that is, the {stator} is empty.
7758a7942,7945
> :stream: A line of identical objects (usually {spaceship}s), each of
> which is moving in the same direction, this direction being parallel
> to the line. Compare with {wave}.
>
7887a8075,8116
> :switch engine channel: Two lines of {boat}s (or other suitable
> objects, such as {tub with tail}s) arranged so that a {switch engine}
> can travel between them, in the following manner:
> ..............**................
> .............*.*................
> ..............*.................
> ................................
> ................................
> ................................
> ................................
> ................................
> .......***............**........
> ........*..*.........*.*........
> ............*.........*.........
> .........*.*....................
> ................................
> ................................
> ................................
> ................................
> ..............................**
> .............................*.*
> ..............................*.
> ................................
> ................................
> .*..............................
> *.*.............................
> **..............................
> ................................
> ................................
> ................................
> ................................
> ................................
> .........*......................
> ........*.*.....................
> ........**......................
> David Bell used this in June 2005 to construct a "bobsled"
> oscillator, in which a switch engine {factory} sends switch
> engines down a channel, at the other end of which they are
> deleted.
>
> :switch engine chute: = {switch engine channel}
>
7909a8139,8166
> The following {c/4 spaceship} (Nicolay Beluchenko, February 2004)
> has two wings, either of which can be considered as a tagalong.
> But if either wing is removed, then the remaining wing becomes an
> essential component of the spaceship, and so is no longer a tagalong.
> .......................*.......................
> .......................*.......................
> ......................*.*......................
> ...............................................
> .....................*...*.....................
> ....................**...**....................
> ..................**.*...*.**..................
> ................**.*.*...*.*.**................
> ............*...***.*.....*.***...*............
> ............******...........******............
> ...........*..*....*.......*....*..*...........
> ...................*.......*...................
> ..........***.....................***..........
> .........*.**.....................**.*.........
> ........*..*.......................*..*........
> ........*.............................*........
> .........**.........................**.........
> .........**.........................**.........
> ***......*...........................*......***
> .*......***.........................***......*.
> ......**..*.........................*..**......
> ..**.*.***...........................***.*.**..
> .*...*.*...............................*.*...*.
> .*...**.................................**...*.
7950c8207
< by {catacryst} and {metacatacryst}.
---
> by {catacryst}, {metacatacryst}, {Gotts dots} and {wedge}.
8045a8303,8321
> :T-nosed p5: (p5) Found by Nicolay Beluchenko in April 2005.
> .....**...............**.**.....*........
> ..*..*.........**.*.***.**......*........
> .*.*.*.....*....*.*.***......**.*........
> *..*.*.******.....*....*.*...**.*........
> .**.*.*..*...***..*.****..*.*.**.**......
> ..*.*..**.*..*..*.**....***.*.*....**....
> .*..*...*..*.*.**....***...*.............
> .*.*.*...***.*...****...*..*.*..**.*..*..
> **.*.........**.*....*.*.*.*........*.***
> .*.*.*...***.*...****...*..*.*..**.*..*..
> .*..*...*..*.*.**....***...*.............
> ..*.*..**.*..*..*.**....***.*.*....**....
> .**.*.*..*...***..*.****..*.*.**.**......
> *..*.*.******.....*....*.*...**.*........
> .*.*.*.....*....*.*.***......**.*........
> ..*..*.........**.*.***.**......*........
> .....**...............**.**.....*........
>
8455,8493c8731,8757
< :tubeater: A pattern that consumes the output of a {tubstretcher}. The
< smallest known tubeater was found by Hartmut Holzwart, and is shown
< below in conjunction with the smallest known tubstretcher.
< .......**.........................
< .......*.*........................
< .......*..........................
< ..........*.......................
< ..........**......................
< ..........**......................
< .........**.......................
< **......**...*....................
< *.*...**..*.*.*...................
< *.....***....*.*..................
< ...*..........*.*.................
< ...**..........*.*................
< ................*.*...............
< .................*.*...*..........
< ..................**..*.*.........
< .....................**.*.........
< .....................**...........
< .....................**...........
< ...............................**.
< .......................*....**.*..
< .......................***..**....
< .......................***..**....
< ........................**........
< ..................................
< ..........................*.......
< .........................**.......
< .........................*........
< ..........................*.......
< ..................................
< ...........................**.....
< ............................*.**..
< ................................*.
< .............................**...
< .............................**...
< ...............................*..
< ................................**
---
> :tubeater: A pattern that consumes the output of a {tubstretcher}.
> The smallest known tubeater was found by Nicolay Beluchenko
> (September 2005), and is shown below in conjunction with the
> smallest known tubstretcher.
> ........*....................
> .......**....................
> .......*.*...................
> .............................
> ..........**.................
> ..........**.................
> .......................***...
> .*......**...*.........*.....
> **.....*..*.*.*.........*....
> *.*...**.*...*.*..........***
> ....*.........*.*............
> ...*...........*.*.....**....
> ...*..*.........*.*....*.*.*.
> .................*.*...*...**
> ..................*.....*....
> ...................*..**..*..
> .....................*.****..
> ......................***...*
> ..........................**.
> ...........................*.
> ...........................**
> ..........................*..
> ...........................**
8515c8779,8780
< :tub with tail: (p1)
---
> :tub with tail: (p1) The following 8-cell {still life}. See {eater}
> for a use of this object.
8673,8674c8938,8939
< cell for Wolfram's Rule 100, a one-dimensional {cellular automaton}
< that is know be universal.
---
> cell for Wolfram's Rule 110, a one-dimensional {cellular automaton}
> that is known be universal.
8689,8696c8954,8960
< Paul Rendell completed a Turing machine construction (described
< in {http://www.cs.ualberta.ca/~bulitko/F02/papers/tm_words.pdf}).
< This, however, has a finite tape, as opposed to the infinite tape of
< a true Turing machine, and is therefore not a universal computer.
< But in November 2002, Paul Chapman announced the construction
< of a universal computer, details of which can be found at
< {http://www.igblan.free-online.co.uk/igblan/ca/}. This is
< a universal register machine based around Dean Hickerson's
---
> Paul Rendell completed a Turing machine construction (see
> {http://rendell-attic.org/gol/tm.htm} for details). This, however,
> has a finite tape, as opposed to the infinite tape of a true Turing
> machine, and is therefore not a universal computer. But in November
> 2002, Paul Chapman announced the construction of a universal
> computer, see {http://www.igblan.free-online.co.uk/igblan/ca/}.
> This is a universal register machine based around Dean Hickerson's
8813a9078,9093
> :Wainwright's tagalong: A small p4 c/4 diagonal {tagalong} that has 7
> cells in every phase. It is shown here attached to the back of a
> {Canada goose}.
> ***.............
> *.........**....
> .*......***.*...
> ...**..**.......
> ....*...........
> ........*.....*.
> ....**...*...**.
> ...*.*.**....*.*
> ...*.*..*.**.*..
> ..*....**.....*.
> ..**............
> ..**............
>
8843a9124,9127
> :wave: A line of identical objects (often {spaceship}s), each of
> which is moving in the same direction, this direction not being
> parallel to the line. Compare with {stream}.
>
8860a9145,9148
> :wedge: A 26-cell quadratic growth pattern found by Nick Gotts in March
> 2006, based on {Gotts dots}. In terms of its initial population,
> this is the smallest known pattern with superlinear growth.
Nowadays we have quite a number of strange speeds, and no particularly good candidate for the strangest. There are similar no-longer-true statements scattered all through the Lexicon, and it's going to take a very careful reading to find them all.:17c/45 spaceship: A {spaceship} travelling at seventeen forty-fifths of the {speed of light}. This is the strangest spaceship speed for which there is any known example...
By this time, the LifeWiki has clearly taken over as the most up-to-date and (mostly) authoritative reference for Life terminology. But Golly is still packaged with the old Life Lexicon, which is still pretty useful just as it is -- or it would be if it were just a little more reliable, anyway.
I'm thinking that in 2016 I'd like to put together a tenth-anniversary update, to patch up any obvious inaccuracies in existing Life Lexicon entries.
As a secondary goal, I wouldn't mind adding any new terms that have cropped up in the last decade, that have really proven themselves to be useful. As a simple rule of thumb, let's say that I'll probably add a new term if an entry for it has already existed in the LifeWiki for a year or two ... asssuming that that entry doesn't have a header suggesting that it's non-notable.
A new definition is much more likely to make it into the tenth-anniversary update if a nice clear simple short Lexicon-compatible text definition shows up in a message in this thread. LifeWiki definitions are often longer than the Life Lexicon can support, and will need to be boiled down to the basics, with extra references and illustrations removed. Bonus points if the odd format of the original text Lexicon is followed exactly. The term is delimited by colons --
:new term:
-- and references to {other terms in the Lexicon} are marked off in {curly braces}. Quoted patterns are in ASCII format -- .=OFF, *=ON -- indented by four spaces.
As usual, I reserve the right to arbitrarily change the rules for accepting and rejecting proposed entries to the Lexicon tenth-anniversary update, as long as I'm the one doing the work of sorting and editing and deciding the details. On the other hand, since the Life Lexicon can be copied and distributed under the Creative Commons Attribution-ShareAlike 3.0 Unported licence (CC BY-SA 3.0), anyone else is very much welcome to take over doing all that work instead of me, and I'll be very grateful.